Understanding ink limits in Photoshop

Ink Limit is the amount of Ink of each color you put on the paper when printing. If your color in a document is 100% Cyan, 100% Magenta, 100% Yellow and 100% Black – you have a 400% ink limit (sometimes called density). Understanding and adjusting your ink limits can improve the quality of your printed piece. MOST commercial printers like to have between 280%-300% ink limit. That means that if you want a nice deep black, you can run something like 60% cyan, 60% magenta, 40% yellow and 100% black – which is a 260% ink limit (or density). Using a higher ink limit, such as a CMYK setting of 100% of all four colors, will generally result in a muddy image, or wrinkled paper. At the very least, you may experience ink offset and extended dry times on your print job. Read on for more on ink limits. You access Ink Limit information in Photoshop by going to Edit>Color Settings and in the Working spaces area, you click the CMYK drop down menu and select Custom CMYK. In this box you can see an area to enter in an ink limit and dot gain. Optimal settings are usually in the range of this:

• Ink Colors: SWOP (Coated)
• Dot Gain: Standard 20%
• Separation Type: GCR
• Black Generation: Medium
• Black Ink Limit 80%
• Total Ink Limit 300%
• UCA Amount: 0%

The Black Ink Limit tells photoshop that the darkest black can be up to X%. If you change that setting to something like 70%-80% you will find that when you convert the image to CMYK, any area that was 100% black will only be 70%-80% black. This results in more detail in the darkest areas of an image. All these settings occur when you convert an image from RGB to CMYK. If the image is already CMYK, there’s not a whole lot you can do to adjust it automatically; though you could still make adjustments with Selective Color or Levels. Your safest bet is to use the North America General Purpose 2 in the Settings drop down menu. Then change the CMYK drop down menu to U.S. Sheetfed Coated v2 and save your settings. The reason you don’t want to just leave the CMYK setting as it appears under General Purpose is that it defaults to a Web press setting. Most print work is done on a sheetfed press.

If you know the file is going to be printed on a Web press, such as for a newspaper ad, change the CMYK setting to Custom CMYK. In the dialog box that pops up, set your Ink Settings to SWOP (Newsprint). You will notice the Dot Gain jumps up to 30% to compensate for newsprint’s tendency to soak-up ink. Now adjust your Total Ink Limit to something between 225% and 240%. I generally leave the black ink limit at 100% for newsprint, then make a special effort to adjust my images to not have too much Cyan, Magenta and Yellow in the darkest black areas. I would love to tell you that there is a standard setting that applies in all cases. Unfortunately, there simply isn’t. The best bet is to ask your printer what settings will work best on their output device and printing press. The most important thing to remember is that you should do the bulk of your color adjustments and composition in RGB mode, saving the CMYK conversion for the last step. Once your image is converted to CMYK, only slight adjustments should be made. To make it easier, be sure to preview your image in CMYK mode when working in RGB (Command + Y). You can read more about Ink Limits and the other settings found in the dialog box above here.

Related posts:

1. Create better PDFs by understanding the formats
2. Create a comic book halftone-dot effect for your Photoshop images
3. Save your sanity, use CMYK Preview in Photoshop
4. Using multiple windows with one image in Photoshop
5. Understanding camera lens terminology on your digital camera