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Here’s a great question that’s just been submitted…

“When turning in files….does it make a difference to the printer (either for processing or printing) whether images are tiff, eps, ai, psd, jpg, etc. files? What is the preferred method…for b&w, PMS work and full color work. What about file names….are there issues with images having really long names or certain characters in them? And anything else that runs along these lines. I have never really worried about the saving component….just that it is 300 DPI….but my designer is under the impression that by changing all our images to Tiffs we will have better color at press. Just wondering your take. Because if it doesn’t matter….its a lot of unnecessary work for us on this end.”

I’m going to break this one down into several smaller segments and address each one since there are a few variables at play here. Let’s start with the first part…

“When turning in files….does it make a difference to the printer (either for processing or printing) whether images are tiff, eps, ai, psd, jpg, etc. files? What is the preferred method…for b&w, PMS work and full color work?…I have never really worried about the saving component….just that it is 300 DPI….but my designer is under the impression that by changing all our images to Tiffs we will have better color at press. Just wondering your take. Because if it doesn’t matter….its a lot of unnecessary work for us on this end.”

Our reader is asking about submitting packaged files in their native state, so obviously he or she knows something about printing and design and has experience in this area. This is one of those great questions because it usually occurs somewhere during the design stage and is forgotten about by the time the project is ready to be submitted. We really have a couple of key formats and differences here, so I’m going to break it down based on how the project is to be printed. Full color and black and white can be grouped together for the purposes of this topic. Images and photos  are also called Raster Graphics and can be saved in a variety of formats, tif, eps, psd, jpg, png, gif and probably a few more. The most popular program on the market for working with images is Adobe Photoshop and you can choose any of these formats to save or export to, so let’s talk about the main ones used in printing and their uses.

• PSD - This is a native Photoshop file format. It is lossless and retains all of that groovy data like layers and stuff that makes Photoshop so useful. When you save your file in this format, it will usually be fairly manageable in size and can be opened and saved again in Photoshop without loss of data. The color will not be affected when a psd file is dropped into compatible layout software, with one caveat…make sure the color in the psd is the same as your project specifies. If you’re project is full color (CMYK) make sure your psd file is CMYK. If you’re printing black and white, make sure your file is grayscale. And since I’m not going to dive into Color Management here, ask your print shop if they prefer to have the color profile embedded or left out. Now that we’ve hit the high points of psd files, you might ask why use any other file format like tif or jpeg or whatever. Here’s my answer: not all page layout software will accept a psd file inserted into the document, so you may have to look at alternatives. Also, since software upgrades seem to happen more often than changes in the weather, your print shop may not have the latest version to open your psd file if changes need to be made on that level, and if you have text in your psd file (which I don’t recommend) that can complicate matters even further due to Photoshop’s rudimentary text-handling abilities.

• Tif - For most practical purposes, tifs are quite similar to psd files with a few notable exceptions. Tif files are another lossless file type, however with the same resolution as psd files, are typically much larger in size. Photoshop layers can be saved in tif files as well, with yet another increase in file size. There are a few compression settings that can be used to reduce the disk space consumed, but the only one I recommend is the LZW compression. It will not affect image quality and can indeed save a little room on your hard drive. The same color rules apply here as with psd files…make sure you have the correct color space for your final output. The main advantage with tif files is that they are not proprietary or software specific, so you can open them with other image editing programs and place the files into a wider assortment of page layout applications. This means different versions of Photoshop can open the same tif files without issues. Now I don’t know how this applies to layers because I haven’t yet run into that scenario, but if I do, I will update this post. There are no color differences between or image quality differences between psd files and tif files, but again…ask your print shop if they prefer the color profiles to be embedded or not because that choice WILL affect final color.

• Jpg - This is undoubtedly the most common filetype today for one significant reason. Digital Cameras. Jpg files are always compressed, and there are many, many ways to compress them.  And there is no real, fundamental way to know how much compression has been applied to the file. If you open a jpg and save it as a jpg, you have just compressed it even further. Do this 2 or 3 times when working on a photo and you’ll end up with something virtually unusable. It is widely accepted as the normal filetype for images, and some photolabs will not accept any other type of file, but we’re not talking about photolabs, we’re talking about commercial printing. You can manipulate jpg files in a wide variety of image editing software, but the jpg filetype will not accept layers in photoshop, so if you like using layers, you’ll have to either save it as another type (like tif or psd) or flatten it and lose your layers completely. The one part about jpgs that adds even more confusion is when working with digital camera files. Each camera brand and model seems to have their own logarithm for jpg comression, but for the most part, high-quality jpgs from 6mp and larger digital cameras will give you a suitable image for use as a full-page (letter-sized) printed piece. But remember…digital cameras capture data almost exclusively in RGB colors, so you will still have to convert the image to CMYK or greyscale before you use it on a printed project, which means you’ll have to save it as something other than a jpg or else you’ll lose image quality.

• eps, png, and gif - Eps files will be covered in the next section, but image files can be saved in this lossless format also, however it’s not very common and with the choice of tif and psd files, isn’t really necessary except for a few very specific applications that we’re not going to cover in this post. Png and gif files are compressed like jpgs and are normally used for web applications, so there’s no real need to include them here.

To wrap up the first part of this post and get back to the original question, it is best to stick with psd or tif files because they are lossless and maintain the quality you started with and offer no difference in color if all of the color settings are the same between the two filetypes. So, if you are using page layout applications that accept psd files and often create psd files that contain lots of modifications, then I see no reason to convert to tif as long as you feel confident that no downstream modifications will have to be made after you submit your files to the print shop.

I have to add one more brief word about image files. If you’re using spot colors (PMS) in your page layout document, you must save your image files as greyscale tif files, and THEN apply your spot color in the layout program.

The reason I separated the question into different parts dependent on final color choice is because there are really only two types of files relating to images you will ever export from photoshop…CMYK or greyscale. Photoshop does not have a spot color system that is even remotely easy to use, with the exception of duotones, and to be honest I can’t remember ever seeing a raster image coming from photoshop (or any other image editing application) that has been successfully saved or exported in a single spot color.

And that leads us to spot color printing with PMS colors. So far we’ve been talking about image (raster) files and the options for saving them in regards to full color (CMYK) printing and black and white printing. Now we need to address another part of the question…ai and eps files from vector programs like Illustrator, CorelDraw and Freehand.

Our designer who submitted the question obviously understands the importance of vector files and why they should be kept as vector files, rather than converting them to raster. (There will be an upcoming post explaining the difference between the two in great detail.) There is no significant difference between ai and eps files with resolution or file size because resolution is not an attribute of vector files. The best way to answer our reader’s question concerning which of these to use in the layout document is very similar to psd vs. tif files. Ai files are native Adobe Illustrator files while eps files are a more generic filetype, so the same rules apply as before. It doesn’t really matter which you use as long as the colors are in the correct color space for final output, except this time we will add spot colors to that.

Why do spot colors matter in vector graphics and not in raster graphics? As I mentioned above, it is best to use a greyscale tif with raster images and convert to spot color in your layout program, but the same is not true with vector files. Since vector files consist of lines and shapes with fill colors already specified, you want the original illustration to be correct from the very beginning, because you cannot change the colors in eps, ai or any other vector files in your layout program. Read that again. It will save you much frustration. Our designer knows this and is simply asking if one file type is better than the other, but I wanted to explain some fundamental reasons why so many different filetypes exist and what they are best used for.

To summarize the questions about filetypes, I will give you my short answer…for raster graphics, psd and tif files are best and as long as the color space is correct and color profiles are consistent with the recommendations from your printer, there will be no difference in color quality or image quality. With vector files, I would recommend using eps files since there are no notable differences in file sizes and you can increase compatibility with other programs. Here again, with vector graphics, as long as the colors are consistent, there will be no differences.

Now to the last question…

What about file names….are there issues with images having really long names or certain characters in them? And anything else that runs along these lines.

This question is purely a difference between PC and Mac platforms. The Mac file system will let you add certain characters to filenames that PC systems will reject. One key example is the slashes “/”. You cannot put slashes in files saved on PC platforms. As for length of filenames, I’m sure there are limits to length, but my rule of thumb regarding these two issue are very simple…keep your filenames short, no more than 16 characters if you can and only use hyphens, spaces and underlines in those filenames. You will probably never know what kind of servers, platforms and archiving systems your print shop uses, and should you ever need to retrieve a previous project from them, you want to feel confident and secure that your files will remain safe. If you do use long filenames and some part of your archiving system or the print shop’s system decides to truncate (shorten) those filenames, you’ll be unhappy if you request those files and discover that none of your links are available beacuse the filenames have all been shortened. It’s not fun…believe me. Stick with short names with safe characters and you’ll thank yourself down the road.

While I believe all of this information to be accurate and complete, if you find something erroneous or have more information to add that may clarify something, please send me a comment or email and I will certainly make any corrections.

Tags: Color Printing, Commercial Printing, Designing for Print, Graphic Design Printing, Layout Graphic Design