Here’s the scenario. You have spent most of the night retouching and colour correcting images. You’ve calibrated and profiled your monitor, hard-proofed on your inkjet printer via a profiled and calibrated RIP and you always view your proofs under controlled D50 lighting. As well, you insisted that the printer supply a proof, just to be sure. It would seem you have covered all the bases. Nothing can go wrong. You will sleep soundly tonight knowing you did everything possible to ensure perfection is achieved.
A few days later you get the call from the printer that your job is ready to go to press. You drive confidently to the printer, windows down, music playing and a smile on your face. When you arrive at the printer you can see that your images are not printing as expected, the images are dark; there is a significant loss of shadow detail. You’re no longer smiling.
So what went wrong? You did everything possible, didn’t you? Well, almost everything. Chances are your proofing setup was targeting a coated stock and not the super absorbent uncoated stock actually being used. Paper plays a key role in how your images will reproduce.
How you converted your images (RGB > CMYK or CMYK > CMYK) and what profile you selected also plays a very vital role in how those images will reproduce on press. Before you convert your images you need to know what paper it is going to be printed on, what type of press and the recommended Total Area Coverage. TAC means how much ink is laid down in the darkest regions of your image. TAC is the addition of all four inks in the your blacks.
So what can you do to ensure your day isn’t ruined?
- Check what ICC profile your image has been converted with.
- Ask your printer what TAC (Total Area Coverage) they recommend for the paper you are using.
- Adobe Photoshop utilizes four ICC profiles for CMYK reproduction and each has a unique TAC. (See Chart)
- Using too high an ink limit will have a negative impact on the quality of your images.
- It is possible to use Photoshop’s “Convert to Profile” command to re-convert a CMYK image to a more appropriate ink limit. For example, if your image was converted using U.S. Sheetfed Coated V2.icc and your printer recommended a Total Ink Limit of 300% you should re-convert your images via the Convert to Profile option to U.S. Web Coated (SWOP) v2.
- If you have no idea where the job will be printed and on what stock it will be printed on, your best option would be to convert your images using U.S. Web Coated (SWOP) v2. This would be the safest option.
Total Area Coverage amounts
for Photoshop Profiles:
|Photoshop Profile||TAC (Total Area Coverage)|
|U.S. Sheetfed Coated v2||350%|
|U.S. Sheetfed Uncoated v2||260%|
|U.S. Web Coated (SWOP) v2||300%|
|U.S. Web Uncoated (SWOP) v2||260%|
Total Area Coverage and Paper Type Chart
|Grades 1&2 Premium gloss/dull coated||175||320%|
|Grades 1&2 Premium matte coated||150-175||300-320%|
|Premium text cover||150-175||268%|
|Grade #5 (SWOP)||133||300%|
|Supercal SCA 5 (SWOP)||133||280%|
|Supercal SCA 5 (SWOP)||120||240-260%|
|Supercal SCB 5 (SWOP)||120||240-260%|
|Uncoated 5 (SWOP)||110||240-260%|
|Newsprint (heatset & Supercal SCC) (SNAP)||100||240%|