From: "Dawn Campbell", dlc@mail.accordsystems.com
Date: Thu, Oct 19, 2000, 5:46 PM
RE: [ColorTheory] CMYK setup questions
Apologies for the newbie questions, but I need to get a yellow pages ad out and this is the first time I've worked with newsprint. I'm new to print, period.The ad was created using Photoshop 5.5. I need to change the CMYK setup for Inks to SWOP Newsprint and the Dot Gain from the current setting of 20% to 35%. The image is a CMYK 300 dpi photoshop file (with type in separate layers), altho the image is B&W (and the type white). I was told to leave it in CMYK mode and not to convert it to grayscale.
A couple of questions: 1. With the image open, does a change to dot gain in CMYK setup actually effect a corresponding (permanent) change in the open image file, or does it only affect how it is displayed onscreen? What do I have to do to embed the change in the file?
2. Similarly, does a change in Ink Colors from SWOP Coated to SWOP Newsprint affect the open file? Does it get saved with the file? Or do I have to convert it? If I have the CMYK settings as I want them when I reopen the file, are they applied at that time?
3. The person who told me what settings to use is using PS 4.0. Are these same settings going to work for 5.5? If not, how would I figure out how to compensate for the differences?
4. I was told to ignore ("not worry about") the rest of the separation settings in the CMYK setup dialog. Does that sound like it's okay? I'm worried she told me to ignore them because they are different than 4.0 and she didn't know what to do with them..... so the easiest path was to ignore them??
TIA,
Dawn
From: Chris Murphy, lists@colorremedies.com
Date: Thu, Oct 19, 2000, 6:02 PM
RE: Re: [ColorTheory] CMYK setup questions
>1. With the image open, does a change to dot gain in CMYK setup actually
>effect a corresponding (permanent) change in the open image file, or does it
>only affect how it is displayed onscreen?Only onscreen.
>What do I have to do to embed the
>change in the file?Use curves, hue/saturation, replace color - etc. to change the CMYK values in the image itself.
You need one of two things to be true:
1.) Calibrated/profiled monitor, with CMYK Setup set correctly for the intended output method - which means getting a separation table or ICC profile from the printer who will be doing this work.
2.) Be familiar with a by the numbers process for the specific output behavior in question.
If one or both of these is not true, you're shooting in the dark and what you get will likely not be what you expect (or see on you monitor).
>2. Similarly, does a change in Ink Colors from SWOP Coated to SWOP Newsprint >affect the open file?
No. Only preview.
>Does it get saved with the file?
The information might be embedded in the file, but it isn't going to help anyone who isn't willing to use that embedded information; and most printers do not use customer embedded profiles in images.
>3. The person who told me what settings to use is using PS 4.0. Are these
>same settings going to work for 5.5? If not, how would I figure out how to
>compensate for the differences?Photoshop 5.5 compensates for dot gain and ink colors differently than Photoshop 4. The same values will not give you the same behavior.
I had a list of dot gain values that correspond to 4 and 5, but I can't find it at the moment.
>4. I was told to ignore ("not worry about") the rest of the separation
>settings in the CMYK setup dialog. Does that sound like it's okay?All of them are important. If they are assuming you have an accurate starting point, then ignoring the rest of the settings may be good advice, but if you're starting with something else who knows. Total ink limit, black ink limit, black generation - all of these will affect the preview on-screen - however this isn't four color printing, but just black. I'd leary about the suggestion you do this in CMYK even though CMY aren't going to be printed. I would think that would result in a substantial change going from screen to print - but perhaps they have a way to compensate for this.
> I'm
>worried she told me to ignore them because they are different than 4.0 and
>she didn't know what to do with them..... so the easiest path was to ignore
>them??Entirely possible.
Chris Murphy
From: Dan Margulis
Date: Thu, Oct 19, 2000, 6:02 PM
RE: Re: [ColorTheory] CMYK setup questions
Dawn writes,>>With the image open, does a change to dot gain in CMYK setup actually effect a corresponding (permanent) change in the open image file, or does it only affect how it is displayed onscreen?>>
The latter.
>> What do I have to do to embed the change in the file?>>
Using your *original* CMYK Setup, convert to LAB, move the top right (shadow) point of the L curve slightly to the left to darken the shadow, change your CMYK Setup to the new settings, and reconvert to CMYK.
>>Similarly, does a change in Ink Colors from SWOP Coated to SWOP Newsprint affect the open file?>>
Same as above.
>>If I have the CMYK settings as I want them when I reopen the file, are they applied at that time?>>
Those settings are history. What you have now in the file now are numbers. How they got to be what they now are isn't really relevant. If your CMYK Setup is correct the image will display correctly, that's all.
>>The person who told me what settings to use is using PS 4.0. Are these same settings going to work for 5.5? If not, how would I figure out how to compensate for the differences?>>
These settings will not work, as there was a major change in dot gain compensation between PS4 and PS5. To figure out how to compensate, download my review of Photoshop 5 from the articles posted at the web site. That has a box giving the appropriate formula.
>>I was told to ignore ("not worry about") the rest of the separation settings in the CMYK setup dialog. Does that sound like it's okay?>>
No. For this type of work (yellow pages 4/c B/W) use Medium GCR, 100% Maximum Black, 240% total ink, 0% UCA.
Dan Margulis
From: HJswim2@aol.com, HJswim2@aol.com
Date: Fri, Oct 20, 2000, 8:59 AM
RE: [ColorTheory] CMYK setup questions
>>the information might be embedded in the file, but it isn't going to help anyone who isn't willing to use that embedded information; and most printers do not use customer embedded profiles in images.>>
As Chris, Dan and Jonathan know, this is one of my favorite topics, having asked all three virtually the same questions as Dawn.
A quick comment about the above response: After I figured out that the only way I was going to get my CMYK data to change was via a file conversion (e.g., profile to profile or profile mismatch), I did a test to confirm this. I took the same file and converted to four different table profiles that I had created simulating four different on-press conditions (e.g., web coated 25/100/280). When I took PS readings from the new files, the values were in fact different and in line with what I would have expected, i.e., "total ink" in the shadow of the web version was much lower than the same spot in the sheetfed version. I also confirmed this by visually inspecting separation lasers, which showed pronounced differences in the files.
In other words, my (limited) experience indicates that whether the printer "uses" the embedded profiles or not, the files themselves are changed to reflect those profile changes. This, of course, is exactly what I'm looking for, since it's more efficient for me to re-output the same file for different purposes rather than custom-changing separate file copies with curves, etc.
Am I wrong?
Harald Johnson
From: DMargulis@aol.com, DMargulis@aol.com
Date: Fri, Oct 20, 2000, 1:39 PM
RE: Re: [ColorTheory] CMYK setup questions
Harald writes,>>After I figured out that the only way I was going to get my CMYK data to change was via a file conversion (e.g., profile to profile or profile mismatch), I did a test to confirm this. I took the same file and converted to four different table profiles that I had created simulating four different on-press conditions (e.g., web coated 25/100/280). When I took PS readings from the new files, the values were in fact different and in line with what I would have expected, i.e., "total ink" in the shadow of the web version was much lower than the same spot in the sheetfed version. I also confirmed this by visually inspecting separation lasers, which showed pronounced differences in the files. In other words, my (limited) experience indicates that whether the printer "uses" the embedded profiles or not, the files themselves are changed to reflect those profile changes. This, of course, is exactly what I'm looking for, since it's more efficient for me to re-output the same file for different purposes rather than custom-changing separate file copies with curves, etc. Am I wrong?<<
No, this will work. You will of course get better results by doing two customized corrections but this often isn't worth the bother.
This whole thing becomes much easier in Photoshop 6, with a command that allows an immediate CMYK-to-CMYK conversion using only Photoshop's built-in setups, without the need for third-party profiles.
Dan Margulis
Adobe Photoshop training classes are taught in the US by Sterling Ledet & Associates, Inc.