This article is a starting point for concepts such as color space, resolution, page setup, and bleed while providing the standards we use for optimal printing.TABLE OF CONTENTSHow Can I Make Sure My Images Will Print Exactly As I Want Them To? Should I Use CMYK, RGB, or Grayscale Images?What Resolution (PPI) Should My Images Have To Achieve Optimum Print Quality?Is the First Page Printed on the Right or Left Side of the Book?How Should I Set Up My Page Numbers?Why Are There Blank Pages at the Back of My Book?How Big Should My Margins Be? And Gutter?What Is Bleed?Should I Include My Cover in the Same File As the Rest of My Book?Will Lulu Insert a Copyright / Title / Index Page in My Book for Me?How Do I Change the Size of My Book?How Can I Make Sure My Images Will Print Exactly As I Want Them To? Should I Use CMYK, RGB, or Grayscale Images?The best way to make sure that your file will appear correct when printed is to download and review the print-ready file that is created from the PDF you have uploaded. The images will appear when printed as they do in the print-ready file. Another way to make sure that your images will print as you’d like them to is by making sure they are in the right colorspace. Lulu offers options for Full Color and Black & White interior printing. Based on the color options you'll use for your book, you should prepare your file as follows:For Black & White books - Use grayscale for the interior file color space.For Full Color books - Currently, our printers use sRGB. For the best results, we recommend exporting your PDF using sRGB color space settings. Using other color space options (such as RGB or CMYK) will result in a color space conversion to sRGB and may cause unexpected changes to the print color.What Resolution (PPI) Should My Images Have To Achieve Optimum Print Quality?We've tested print quality at various resolutions and found that 300 ppi is the optimum resolution. 600 ppi is our limit at this time, but any improvement in print quality over 300 ppi is not noticeable, and the file size is huge.We suggest that you work at 300 ppi, but also make sure that your image or file is at the correct size. All images must be fully formatted before inserting them into your document. This includes adjusting size and resolution using a photo editor like Photoshop or you can use an online resolution converter like Convert Town.Is the First Page Printed on the Right or Left Side of the Book?Printing is not available on the inside of the front and back covers, except for our Comic Books and Magazines. This means the first printed page of your book will be on the right-hand side, opposite the inside front cover.The odd-numbered pages in your print-ready PDF file will display on the right and even numbered pages on the left.How Should I Set Up My Page Numbers?When creating your book, make sure that your title page falls on an odd-numbered page (on the right-hand side of your book) and the copyright page falls on an even-numbered page (on the left-hand side of your book). Here is a helpful guide for perfecting your page numbers in Microsoft Word. Why Are There Blank Pages at the Back of My Book?The extra white pages you can see at the end of the book are not a production defect, but rather a byproduct of our print-on-demand process. The machines used to print your book are printing thousands of pages per minute, so they stack multiple spreads across the width of the paper roll. Sometimes, white pages will appear at the end of the book as a result of this process. Because this is done per machine, per project, and per order, it can be difficult to predict when white pages may appear, and how many.All that said, we do not charge an extra cost for any blank pages added. Additionally, you should not need to adjust your cover design to accommodate if a few extra leaves of paper are added in production. If this is the case, then please contact support so that we can further assist you.How Big Should My Margins Be? And Gutter?Safety margin refers to a recommended area between the final trim size and the content in the formatted file. All pages are trimmed to size, making it critical to stay within the safety margin, both for the aesthetic of your book and to ensure no content is lost. We recommend that important images and text be kept 0.5” from the trimmed edge of the book. For example, a 6” x 9” interior page would have 0.125” bleed, with the safety margin 0.625” from the bleed edge of the page.The “gutter” is a typographical term referring to an additional margin added to interior pages to compensate for the part of the page made unusable by the binding process. In a facing pages layout, the gutter margin is on the inside of both pages. Books of less than 60 pages don’t normally need to include a gutter, but files with higher page counts should consider using a gutter. For more information, use this table:Page CountAdd to Interior MarginRecommended Interior MarginRecommended Interior Margin (full bleed)Less than 600" or 0 mm0.5" or 13 mm0.625" or 16 mm61 to 1500.125" or 3 mm0.625" or 16 mm0.75" or 19 mm151 to 4000.5" or 13 mm1" or 25 mm1.125" or 29 mm401 to 6000.625" or 16 mm1.125" or 29 mm1.25" or 32 mmOver 6000.75" or 19 mm1.25" or 32 mm1.375" or 35 mmWhat Is Bleed?Bleed is a publishing industry term used to define printing that goes beyond the edge of where the sheet will be trimmed. The “bleed” is the area trimmed off. For example, if you have pages with images that extend all the way to the edge of the page, you would need to run the image to the “full bleed” edge of the page. We have a guide/article for you to review with more specific instructions for uploading a file with full bleed: What is Full Bleed?Should I Include My Cover in the Same File As the Rest of My Book?No. Your cover should be completely separate from your interior file. You will upload your cover file after you upload your interior file and choose your book specifications on the Design step.Will Lulu Insert a Copyright / Title / Index Page in My Book for Me?No. You will need to upload your completed file to the Lulu website. Lulu will print what you upload. We will provide copyright page wording that you can use when you start your project. How Do I Change the Size of My Book?Lulu's system detects the dimensions of the file that you upload and matches the file size to the corresponding book size offered on Lulu. You can view all offered book sizes on this page. So, if you want to create a 6 x 9 inch book (US Trade Size), upload a 6 x 9 inch sized file (or 6.25 x 9.25 for a full bleed file.)