Softback Books Artwork Preparation Guide

We've tried to give you helpful and complete information here. That means there is quite a bit of it as we have to cover all of the options you DON'T want as well as all of the options you DO want. Don't panic! Have a nice cup of tea and a good read. Deathless prose it is not, but it will save you much time and frustration. Don't worry, you are in safe hands. Inky has printed books for thousands of customers over many years, ranging from large publishers to nonagenarians who have never printed a book before. Once you have read this guide, you can call our friendly Helpdesk to discuss anything you need more help with. But, please read the guide first.

Why should you bother with all this?

Getting a job commercially printed requires you to prepare your artwork in a specific way. Once you understand this, it's easy to do and you'll get the results that you want. If you don't follow these simple steps, then you may end up with a job that you're not happy with.

Is proofing the same as proof reading?

It's worth remembering that when we proof your book we just check that it is technically capable of being printed. We don't proof read it, we don't check it for factual errors, we don't check or critique the way that you've laid it out, and we don't call you for a chat if we dislike like the colours you've chosen. We're just the printers. To understand more about proofing and how the proofing process works you can read the help section:

HELP > ARTWORK > PROOFS (opens in a new window)

Is creating or editing your original artwork included in the price?

The prices you see on the web site are from your print ready PDFs. We don't design your cover for you inclusive in that price, we don't add photographs or illustrations, we don't alter layout or correct any form of mistakes you may have made. This is purely a printing service. We're very happy to do additional work for you. If this is of interest to you, please call to the helpdesk on 01452 751900 to discuss.

What electronic format do I supply my book in?

You need to supply us with 2 PDF files, or 3 if you are having hot foil printed on the cover. The first PDF should contain your cover artwork. It should be a one page PDF if the cover is printed just on the outside or two pages if the cover is also printed on the inside. The second PDF should contain artwork for the book block (inner pages). The third PDF should contain the artwork for the cover hot foiling. That's it in a nutshell, but please read on for the detailed information!

Watch out for cracking on the hinge.

The hinges are glued and creased parts of the front and back covers that run parallel to the spine. They are there so that the book opens nicely and to improve the strength of the binding. As the hinge is opened and closed repeatedly, you may find that ink cracks along the length of the hinge. If your artwork is blank, or a light colour at the hinge, then this will not be a problem. If you have a dark colour printed on the hinge, we highly recommend that you specify laminating for the cover.

How many pages are in my book?

This can cause some confusion. A leaf is a physical sheet of paper in your book block. Each leaf comprises two pages. One on the front of the leaf, one on the back. For example: a 100 page book block has 50 leaves and 100 pages. Still confused? Visualise picking up a book. Now open the book anywhere. Look at the recto page (the right hand page) now turn the page and look at the verso page (the left hand page). They are different pages on the same leaf of paper. What about blank pages? A blank page is still a page, it's just a page that is blank.

Understand the different types of printing.

This is just a straight repeat of the information on the product page and strictly speaking not part of the artwork preparation guide. It bears repeating just in case you missed it.

Why not request some samples from the helpdesk so that you can see the quality of the printing before ordering?

There are four different options available:

All B&W (Standard Quality). Standard Quality Black & White is printed on the latest generation digital production printers. The quality is very good, resulting in crisp text, graphics and photographs. The print quality of photographs is good, and works well for many types of books, but this is not the highest print quality that we can offer. We do not recommend high toner (ink) coverage with Standard Quality printing, as a general rule you should not exceed 30-40% toner coverage.

All B&W (High Quality). This is our highest quality black & white printing for near photographic reproduction. Some people print very large areas of solids (i.e. covering nearly all of the page) when selecting B&W printing and although this can produce striking results, it is not recommended (you will get better and more consistent results using CMYK Rich Black).

A mixture of Colour and High Quality B&W. If you require some Colour pages and some Black & White pages, choose this option. It is not possible to mix Standard Black & White and Colour in the same book.

All Colour. Full colour printed on a colour digital press for near photographic reproduction. These presses are used for photobook printing and you should choose this option if that is the type of finish you wish to achieve.

Useful terms.

Understanding some of the lingo is useful as we'll use it when an exact meaning is required. Plus it may come up in Trivial Pursuit one day.

Recto pages. In languages written from left to right, a recto page is on the right hand side when a book is open. It is printed on the "front" of a leaf.

Verso pages. In languages written from left to right, a verso page is on the left hand side when a book is open. It is printed on the "back" of a leaf.

Artwork. This is a generic term, meaning the files that you send to us to print. These are normally PDF files in the format specified in this guide. In this context, this term doesn't refer to photographs or drawings, it simply means your finished work, which may incorporate text, drawings and photographs. It does not mean the file that we send back to you to check, that is the proof.

The Book Block. A softback (AKA a perfect bound) book physically consists of two parts. The cover and the Book Block. The Book Block comprises all the leaves of your book, bound together as a block. So, we call it a... well you get the idea.

Two or three PDFs

Unless you have made special arrangements, you should send us 2 PDF files, or 3 if you are having hot foil printed on the cover. The first PDF should contain your cover artwork. It should be a one page PDF if the cover is printed just on the outside or two pages if the cover is also printed on the inside. The second PDF should contain artwork for the book block (inner pages). The third PDF should contain the artwork for the cover hot foiling. That's it in a nutshell, but please read the sections about creating your cover, book block and foiling for detailed information and help.

If you want to learn more about creating a PDF and why it's necessary for the curious, please read our little guide here:
CREATING A PDF

Tips on choosing software to create your book

If you haven't already started work on your book and are not sure what software application to use, have a read of our handy little guide for some tips:

WHAT SOFTWARE SHOULD YOU USE TO CREATE YOUR ARTWORK?

Tips on creating PDFs

Use the "commercial print" preset. Always make sure that you select the "PDF X/1a" preset when using Adobe products to create a PDF. Other manufacturers products will vary, but try to choose the "commercial print" preset if available as this will tend to get rid of any common nasties while the PDF is being created.

Make sure that you set the correct page size. For both the cover and book block PDF. This is the number 1 reason why artwork fails preflight checks during proofing. Make sure you use the correct page sizes both when setting up your artwork and when you create your PDF.

No Printer's Marks. Please don't add any "printers marks", they interfere with our pre-press procedures (i.e. slow us down and literally get in the way) and we will just delete them anyway. They are named literally: Printer's Marks: the marks printers make.

Embed fonts. If there is an option to "embed fonts" when creating your PDF, please turn it on. Don't panic about it though, our standard "fix ups" during preflight include embedding the fonts that you forgot to embed. Of course we can only do that with fonts that are available and licensed for us to use.

Check the PDFs before uploading!

Don't just output the PDF and upload it. Check it before you send it! Is the page size correct? Hold on a second, I think you skimmed that a bit too fast! I'd better mention it again: check that you set the correct page size!

Tip: Open your PDF in Acrobat Reader or Pro and point your mouse cursor at the bottom left of the page. Your page size is displayed there.

What about TIFFs or JPEGs?

These formats are not accepted for books. To be clear: the images within your PDF files can of course be TIFFs or JPEGs. We just can't accept (for example) 500 separate JPEG files as your 500 page book block. The book block needs to be supplied as a PDF, the images within the book block can be TIFFs or JPEGS.

Cover Layout Guide Templates.

The utility to create your guide template is in your Admin area of this web site. Unless you are a very experienced designer, a guide template will really help. You can generate a FREE template that is accurately sized, including the spine. This helps you lay your cover out at the right size and put all of the elements in the right place. It's not a template that you edit, you will need to use it as a guide along with whatever software you've chosen to create your book in. Here is a 3 minute video tutorial on how to generate your guide template.

How to generate a book cover template using the Inky online tool

Need some help?

If you can't create your cover yourself, don't panic! Here are some ideas that might help. Please call the helpdesk to discuss them in more detail.

Cover Layout Service. If you can't create your cover yourself, this is a low cost option which can help. Creating accurately sized and laid out artwork for your softback book cover can be a little tricky if you haven't done it before. Our prooofing team is very experienced and what might take you ages, will take them only around half an hour. A small fee applies for this service and we provide you with a finished PDF to work from. Please remember that this is not a full graphical design, it is a simple cover layout service from text and images supplied by yourself. Please speak to the helpdesk for more details.

Artistic Cover Designs / Graphic Design. Inky no longer has a full time Graphic Designer on staff. For more complex or artistic cover designs, we recommend that you employ an experienced Graphic Designer who can quote you for cover design from your brief.

Video tutorials.

We have several step-by-step tutorials. You may want to read the whole of this section before you watch them as they will make more sense then.

All of our video tutorials are currently hosted on YouTube and will open in a new tab.

Scribus. This video takes you step-by-step through creating the artwork for a printed case in Scribus. This is quite an old video and there have been some changes since it was created. Scribus is an excellent FREE Desk Top Publishing (DTP) application. Like all tools, you will have to learn how to use it. It's designed for varied and complex tasks, so there's a lot to it. The Inky tutorial concentrates on just the elements you need to create a cover and shows you "how to" step by step. Since we created this video, the softback book product page has been updated and now works out all of the dimensions for you. So you can ignore the bits where we explain how to calculate these. There is also a new online tool (available through your Admin area of this web site) that generates an accurate template for you to show you exactly where to place all of the elements on your cover. In the next version of this video, we'll show you exactly how to use that with Scribus.

How to create a book cover using Scribus

Canva. This video takes you step-by-step through creating the artwork for a printed cover in Canva. The tutorial uses the example of a hardback cover, but the concepts are all the same. Isn't Canva great? It's a free online app that's easy to use and let's you create lots of printable things. It's not so great at accurately creating book covers, however by using Inky's dynamic book cover template generator AND Canva, it's a doddle. In this video tutorial we show you how to create a print ready, accurately laid out book cover in about 11 minutes.

How to create a book cover using Canva and Inky templates

Apple Pages. This video takes you step-by-step through creating the artwork for a printed cover in Apple Pages. The tutorial uses the example of a hardback cover, but the concepts are all the same. Pages seems to have come on quite a bit in recent years and while it wouldn't be our number one choice for creating a book cover, it's perfectly usable. It doesn't play nicely with templates, but has a nicely implemented ruler & guide system, so we show you how to set that up using the Inky template. In this video tutorial we show you how to create a print ready, accurately laid out book cover in about 8 minutes.

How to create a book cover using Apple Pages and Inky templates

We're working on new tutorials, so please contact the helpdesk if you are looking for help with any other app.

The spine.

When you use the price calculator to work out a price and order your books, it will also tell you the APPROXIMATE thickness of the spine (it's in the "notes"). Please remember that this is only approximate and the thicker the book, the larger the discrepancy might be. If it's vital that your spine measurements are precise, we recommend that you order a hardcopy proof, inspect that and adjust your artwork accordingly before committing to the whole print run.

Be realistic about printing on the spine. If you have a very thin spine, don't expect to be able to print on it!

Why is the calculated spine thickness "approximate"? We use two basic measurements to calculate spine thickness: the paper thickness of the book block and the card thickness of the cover. We have an process to add an "approved paper" and until we go through the process again to change the paper for whatever reason, we will always use that specific paper for that specific product. When we add an approved paper, the mill will tell us the "nominal thickness" for each weight. You can think of that as the "target" thickness that the mill aims for and the specification of the paper that we use generally has a plus or minus tolerance of no more than 8% of the weight and thickness. For instance, a 130gsm gloss paper may have a nominal thickness of 98 microns, but be delivered to us at 92 microns. That's well within specification and we must accept that consignment. We measure the first batch of paper that we receive from the mill with a very precise micrometer and this is the thickness that we use in our spine width calculator (we have found that this is much more accurate than using the mill's own nominal values). So, you can see that from batch to batch of paper that the mill manufactures, the actual thickness of the paper can vary slightly. It is not a large variation and does not affect the quality of your product, but the ACTUAL thickness of your spine can be different to the CALCULATED value, especially if you have a large number of pages.

Visualise your cover.

When designing your cover, it helps if you visualise what it physically IS. Imagine a softback book. Now (as you briefly turn into the Incredible Hulk), you rip the whole cover off in one piece (don't do this). Open the cover flat and put it down on a table top. The rear cover is on the left, the spine is in the middle and the front cover is on the right. That's how you need to design your cover. But with less ripping, obviously.

Creating the artwork for your cover.

There are lots of different software applications that you can use for this, so this section is not a step-by-step how to. It covers the basics and gives you the information that you'll need. Don't forget: you can use a Guide Template to make things easier and we do have step-by-step video tutorials for many DTP tools and apps.

1. Create a custom page size

Using your chosen DTP application or Word processor you need to create a custom page size that matches your cover size. See below for what that size should be. It's no good trying to bung it all on a US Letter sized page and hoping that will work! You've got to figure out how to create a custom page size in your software. You will need ONE page for covers printed on the outside and TWO pages for covers printed on the inside and out.

The cover page size for STANDARD sized books. The good news is that unless you need a custom sized book, we've worked all the measurements out for you. Look in the "notes" section of your quote (it's also recorded in your order description if you've got that far) for the cover artwork page size.

The cover page size for CUSTOM sized books. If you are ordering a custom size book, then you will have to calculate the page size to use for your cover. Don't worry, if you need help with this, just call the helpdesk for a chat! Here is how to work out the height and width:

• Height = book block height PLUS 4mm.
• Width = book block width TIMES 2, PLUS the width of the spine, PLUS 4mm.

Example, an A4 book with a 12.5mm spine. The COVER ARTWORK dimensions should be approximately as follows:

• Height = 297mm, PLUS 4mm, EQUALS 301mm.
• Width = 210mm TIMES 2, PLUS 12.5mm, PLUS 4mm, EQUALS 436.5mm.

2. Draw yourself some guides

Don't forget: if you use our free Guide Template, you don't need to do this. If you are using our Guide Template, place the template onto the page. Exactly how you do this will depend on the software that you are using. We have step by step tutorials for some popular applications.

We can't tell you how to create these guides, that depends on what software you are using. The first guide is a vertical line 2mm from the left edge of the page. The second guide is a horizontal line 2mm from the top of the page. The third guide is a vertical line 2mm from the right edge of the page. The fourth line is a horizontal line 2mm from the bottom of the page. What you have now drawn are the guide lines which show you where the start of the BLEED area for your cover is. If you do not understand what a bleed area is and what it is used for, there is an explanation here:

BLEEDS

Now draw your fifth guide: a vertical line 2mm PLUS the width of the book block from the left of the page. So, using an A4 book as an example, this would be 2+210 = 212mm. This guide shows you where the left hand side of your spine is. Now draw your final guide: a vertical line 2mm PLUS the width of the book block PLUS the width of your spine. Using an A4 book with a 12.5mm spine as an example, this would be 2+210+12.5 = 224.5mm. This guide shows you where the right hand side of your spine is. Now you have all of these guides, you can see exactly where your front and back cover, spine and wrap around areas are. But it would have been much easier to use the Guide Template.

3. Lay out your cover

The cover is laid out in the same order as the image above. Use either the guides that you've drawn, or the free Guide Template to make sure that you put all of the elements of your cover in the right place. Exactly how you do this will depend on the software that you are using. We have step by step tutorials for some popular applications. Don't worry: you will get a soft proof to check that will confirm the actual position of the spine and the edge of the cover.

Artwork in the bleed area? What to fill the bleed around area with? Usually it's just a continuation of the background colour or graphic.

Very simple hot foiling

Some people will have simple requirements for hot foiling, for example a line of text for the title and a line of text for the author name. In this instance, it is sufficient to supply the text at the correct size and font in your PDF and give us instructions via the helpdesk on where you wish to place it. A simple message along the lines of "Please centre these two lines on the front cover" will suffice.

Everything else

You should provide the artwork for the areas to be hot foiled as one page in it's own PDF file. Make the page size the same as your cover artwork. This allows us to exactly position your hot foiling where you want it to be. If you can't supply your foiling artwork like this, please call the helpdesk and we'll figure a way around it.

All of your artwork for hot foiling MUST SIMPLY BE IN BLACK. Do not send a mixture of colours, you will not like the results! Text and simple graphics work best with hot foiling. If you wish to print a graphic on your cover, keep it simple and solid black. Do not use tints (a percentage of black), they do not translate well to hot foiling.

Important note. If you have ordered a printed cover and hot foiling, DO NOT attempt to mix your full colour cover artwork and your hot foil artwork on the SAME PAGE. That simply will not work.

Spine width. We cannot currently hot foil onto spine widths less than 8mm.

General information about foils

We stock an extensive range of high quality foils manufactured by Kurz.

We display a "descriptive" name for each foil colour, i.e. Cloud Grey. Foil manufacturers do not give a descriptive names, just numbers! So these descriptive names have been made up by us at Inky in order to help you differentiate between shades when you are ordering. After each name we give a reference in brackets, for instance L362. This gives the manufacturer's reference, in this case Luxor 362. You should ask for a foil swatch sample, especially if the exact colour of the foil is important to you.

If you have access to a Kurz swatch book, you can look the colours up yourself using the reference number in brackets. L stands for Luxor, C stands for Colorit, AF stands for Alufin.

You can select one foil colour using the instant online quotation. This is just to keep the instant quote generator as simple as possible. If your design requires multiple colours, we can foil as many different colours as you want. However you'll need to speak with the heldesk to get a quotation for multi-coloured hot foiling.

Clear gloss foil imparts no colour to the print, but it is often applied on top of a printed area, giving a highlighted, textured affect. It also looks fantastic with no print below and using a deep impression.

Pearl foil is translucent. If applied on top of a printed area, you can see the printing underneath, but the colour is changed with a the pearlescent lustre.

Matt foils are exactly that. They can look very much like traditional letterpress or lithographic inks. The main difference is that foils are completely opaque. This is a great advantage as it means you can print light colours onto dark coloured card. The foiled area will show bright and true, whereas the colour of inks will vary according to the colour of the card that they are printed onto.

Gloss foils have a high gloss shine.

We also usually carry dull gloss gold and silver foils. If you would like this type of finish for your project, please contact the helpdesk to discuss.

We can apply one foil colour on top of another. This does not behave the same as inks: if you print a red dot on top of a white area, you don't get a pink dot, you get a red dot as the foils are opaque. The only exceptions to this are where we note that the foil is translucent or clear.

Please bear in mind that hot foiling is not the same process as printing and what is achievable is different. For example, you cannot create a half tone screen with foiling. Please read the artwork preparation guide for more information.

In some circumstances, we can special order colours that we don't normally stock. Please contact the helpdesk if you'd like to discuss this.

There may be slight colour differences between different batches manufactured.

Send us your artwork as one PDF

This is covered in "What format should my softback book be in?" but just to remind you, your book block artwork should be sent to us as one PDF. If you haven't already read that section, please read it now.

Page layout

Seperate pages. The PDF should contain seperate pages, NO SPREADS of any kind (that includes printer's spreads). Don't try to do any imposition: just the pages, in the right order, one at a time.

Page order. We're not trying to insult your intelligence, but this issue has come up a few times now, and has caused problems, so it's worth making crystal clear. When you open a softback book, page one of your book is on the recto (right hand) side facing you. It is not printed a page or two in, it is not printed on the back of the cover. This is of course just like every softback book you have ever seen. If you want your book to start printing on a verso (left hand) page, you need to insert a blank page. That blank page will be "page one" of your book and should be the first page in your book block PDF.

Page sizes. The page size should be the size that you have chosen for your book, for example an A5 book will be 210mm x 148mm. If your pages are BLED, then you need to add 2mm bleeds all round. If you do not understand what a bleed area is and what it is used for, there is an explanation here:

BLEEDS

Margins. We recommend that you use a minimum of 12mm margin on the top, bottom and outside edge of your page and 18mm on the inside of your page. You may find this difficult to lay out if you are not used to creating books, or you don't have DTP (Desk Top Publishing) software. In that case you should consider making all of the margins at least 18mm. Larger books should have larger margins. For example, a "C" sized may will look better and be easier to read with a minimum of 25mm margins. Remember: these are general guidelines. Many designers completely ignore them because their specific requirements are different, for example printing notes in the margin area is often used with text books. A good common sense rule is: if in doubt, print a proof copy and then make your necessary changes after examining that.

Page numbering. It may seem obvious, but we recommend that you always number your pages. There a few different ways to do this, i.e. numbering prefaces and appendices seperately and these are all fine. Be consistent in where you put your numbers. If you want numbers on the outside of each page and your book is in a left to right written language, remember that on right hand ("front" or recto) pages the number should be on the right hand side. On left hand ("back" or verso) pages, the number should be on the left hand side. Desk Top Publishing software (DTP) normally has tools to help you with much of this, but word processing software may not. The easy alternative is just to put your numbers in the middle!

Blank pages. We do not insert blank pages! You may think that it is just common sense that chapters should start on a recto page and this will automagically happen, but it doesn't. If the previous chapter ends on a recto page and you want the next chapter to also start on a recto page, insert a blank verso page before the new chapter. We print exactly what you send us, so if you want a blank page, insert a blank page. Blank pages count toward your black and white page count.

Pages and spreads. The PDF containing your inner pages (the book block) should simply consist of pages, not spreads. A spread is printing terminology that means adjacent pages where artwork spreads out over both pages, for example a photograph. While designing a book, these adjacent pages are often viewed side by side and in some applications you can create your PDF with these spreads as one joined page. You must not submit a PDF with spreads, just the separate pages please. Although spreads are often used in softback and hardback books, you need to remember the limitations of this binding method, i.e. this type of book does not lay completely flat when opened and therefore the centre of your spread will be obscured by the spine.

Typography. Typography primarily covers the font type, style, size and position of the text used in your book. Consideration should also be given to the line spacing, margins, page numbering and more. This is really beyond the scope of this guide, but there are several good books on the subject and some useful information can be found online. Here are a couple of general pointers that may be of some help:

• Text will generally look better if it is justified, i.e. with the words spaced so that lines have straight and even margins.
• Don't make the font sizes too small. It's difficult to give you a firm "use 12 point" rule, as each font will vary. In general, anything under 10pt in any font is likely to be too small. Print out a page in the font & size you are thinking of using, take a good look at it and then show it to other people. Take a trip to the bookshop and look at a few books. Does your font look smaller than is generally used?
• Use a small number of fonts and use them consistently. We've seen some very ugly books that have used a jumble of different fonts. Keep it simple and use fonts for specific purposes. For example; one font for your text, one font for headings, one font for illustration titles. Three fonts should be plenty for most books, but some reference books will need more.

Do I need one?

The first thing to note is that there is no legal requirement for you to have an ISBN number and it does not confer any form of copyright protection. It's simply a product number that will be useful if your book is to be sold in book shops. You should also be aware that when using ISBN numbering, there are strict rules on what changes are permitted to the book after publication that must be adhered to.

How do I get one?

The UK ISBN Agency is run by Neilson Book. If you want a UK ISBN number for your book, this is where they come from. The vast majority of people get their ISBN numbers from Neilson. In the past, you have had to buy a minimum block of 10 ISBN numbers, but that's changed now and you can order a single number if you want. It's a bit of a fiddle, but the end result is that YOU are the publisher of record. If you get your ISBN number elsewhere, for example from the service that prints your book, then THEY are the publisher. This can cause you problems later, so it's sensible to bite the bullet and deal with buying your own ISBN numbers up front.

You can read about the Neilson ISBN Agency here:

https://nielsenbook.co.uk/isbn-agency/

You can buy your ISBN number here:

https://www.nielsenisbnstore.com/

Neilson have some excellent information on their web site about how to use their service. When you complete the necessary form, they will also register your book details on the Publishers International ISBN Directory and the Nielsen Book's Publisher Database. You should read up on this. These are used by booksellers and libraries to provide information for customers.

Can Inky sell me an ISBN number?

In theory we can, but as the Neilson route is relatively simple, low cost, and has clear benefits to you we never do this these days.

Can Inky create me an ISBN bar code?

Yes, Inky has the software to create ISBN bar codes. We make a small charge for this and email you the bar code in PDF format ready for you to insert into your artwork. You can order this at the same time as ordering your books, or speak to the helpdesk to add it to your order. You must have the ISBN number first before we can generate a bar code for you.

What is "Legal Deposit"?

You should also remember your obligations under "Legal Deposit", if your book is to be published and distributed in the UK. If you have an ISBN number and intend to distribute your book for sale in the UK, you should ensure that one copy is deposited with the British Library. You also have an obligation to supply a copy to the 5 Legal Deposit libraries. This deposit is only legally required if a claim is made by the libraries within 12 months of publication, but in many cases publishers will make this deposit as a matter of course.

The Bluffer's guide to RGB and CMYK

RGB (Red, Green, Blue) are the basic components of the colours emitted by your monitor. All the colours that you can see on your monitor are made up from RGB in different proportions. CMYK (Cyan, Magenta, Yellow and blacK) are the ink pigments used to reflect light back to you from the printed sheet. The full colour images that you see on a printed sheet are actually made up from complex patterns of CMYK. RGB colours must be converted to CMYK so that they can be printed. This conversion is usually hidden from you when you are using a desk top printer. Because RGB has a wider gamut (range of possible colours) compared to CMYK, not all RGB colours can be printed accurately in CMYK. For this reason, professional designers will usually design their artwork in CMYK and preview it on screen in simulated CMYK.