Selwyn,
One answer is to create your content in the Y Channel only.
However, I’m wondering what your Colour management settings are as 0,0,100,0 is normally respected in all common CMYK profiles.
The only time I’ve seen the sort of effect you are describing is when converting from one CMYK colour space to another CMYK colour space with perceptual intent.
Of course, if you are working in an RGB document and reading CMYK values in the Info palette than what you describe is entirely understandable and expected behaviour.
Yes Len. This is what I am doing – working in an RGB document and reading CMYK values in the Info palette. Thanks for letting me know it is understandable and expected behavior.
Thanks, Selwyn
working in an RGB document and reading CMYK values
There’s your problem right there.
If you want a specific CMYK value, you have to work in CMYK
What you are currently doing amount to converting a CMYK value to RGB and back to CMYK again
"What you are currently doing amount to converting a CMYK value to RGB and back to CMYK again"
Actually more like converting a CMYK value to Lab> to RGB> to Lab, then back to CMYK.
Dear Jason:
I created Photoshop files in RGB, and imported them into Pagemaker. From Pagemaker, I exported them as PDFs and took the PDFs to a professional print shop to have a run of 1000 printed in CMYK on an offset press. Before I did this, I had a few digital prints made (at another shop) of the PDFS and the yellows printed yellow and the blues printed blue. It looked fine and I gave these prints to the offset press shop as examples. The offset press shop – printing from the same PDFs, presented me with a proof in which the yellows had a strong greenish tinge, and the blues also turned greenish. This print shop said they needed to color correct my original files. They said they could not remove the greenish tint at the ink level.
I went back to my original Photoshop files, and put the eyedropper tool over the yellows and blues that turned green (in the offset printer’s proof but printed fine on both my inkjet, and at the shop that did a few digital prints), in order to write down the values in both RGB and CMYK. I then created a sample file (to send to the offset printer shop) with 5 yellow squares directly from the swatches palette, and noted that the yellows in my files were almost identical to the yellows in the swatches. So it seems to me that my files cannot be made any "yellower" in the Photoshop original. I just wanted to know the RGB and CMYK values reported by Photoshop (in the info palette) so I could send these values to the printer, and ask what he thought I should change them to to remove the greenish tinge. There seems to be very close to zero wiggle room to change these values, and it seems to me that the printer has made some global error in preparing the proof as the whole file has shifted greenish.
Can I send a PDF to this board, or to you, for your comments?
If so, how do I do this?
Thanks,
Selwyn
When working for press, work in CMYK and make sure your colours stay CMYK when creating your PDF
Can I send a PDF to this board, or to you, for your comments?
You can post a link to it.
"When working for press, work in CMYK and make sure your colours stay CMYK when creating your PDF"
Nomad,
If I go back to my original files, and convert to CMYK, and adjust hue, brightness, saturation etc. to get rid of the greenish tinge (which seems to show up when I convert from RGB) – and then import into Pagemaker and from Pagemaker export as a PDF, is there anything special I have to do to make sure I STAY in CMYK and don’t somehow revert to RGB?
Thanks,
Selwyn
I haven’t used PM since verson 4 or 5, so I can’t tell you specifically. In InDesign, I can specify the colour space of the PDF and whether or not I want the colours converted to a specific profile or leave them unchanged.
All I can tell you is to explore the options.
Or ask in the PM forum
Thanks Nomad. Good Advice.
Selwyn
"which seems to show up when I convert from RGB"
That happes within photoshop? Sounds like one of your profiles may be hosed.
Jason:
The shift towards geen when I convert from RGB to CMYK is very subtle. I think its normal.
(Of course I may just be saying this because although I’ve used Photoshop for years, I don’t know what "profiles" are. Whatever they are, they are probably at the default setting)
I know this makes me sound like a total beginner, but I am actually quite adept at Photoshop. It is (as you know) an incredibly deep program.
Do us a favor, go to Edit>Color settings.
What are your RGB and CMYK settings – which profiles are you using?
Not sure what you are asking but:
North America General Purpose 2
RGB: sRGB IEC61966-2.1
CMYK: U.S. Web coated (SWOP)v2
Is this what your were asking for?
Thanks, Selwyn
Selwyn,
If going to print you should be working in CMYK. Unless printing to a web press you would be better advised to use the US Sheetfed profile for your working space (although there isn’t much between that and the web profile).
Don’t take too much notice of the display in PM – it is likely to be fairly horrible with CMYK images, but it is only the display!
Also, if you must do some operations in RGB, then setting your RGB working space to Adobe RGB (1998) will give you better conversion to CMYK than will sRGB.
Thanks Len:
Should I use US Sheetfeed coated v2 or US Sheetfeed uncoated v2?
I don’t know what a web press is. I am having hard copies printed on a four color press at a print shop. Do I have to ask them if they are using a web press? (I realize this question must be very funny to you, but to me it really is a question since I don’t know what the term web press refers to. I don’t even know if it refers to a physical press).
I have always worked in RGB – kind of automatically – and it works just fine and prints fine to my inkjet and to digital printers at professional shops. This is my first go at having a big run done at a four color press, so all this is new to me.
Thanks,
Selwyn
The term web press pre-date the World Wide Web
See here for details: <
http://desktoppub.about.com/cs/printing/g/webpress.htm>
Should I use US Sheetfeed coated v2 or US Sheetfeed uncoated v2?
Talk to the printer
and it works just fine and prints fine to my inkjet and to digital printers at professional shops.
Inkjets are made to accept RGB files.
Thanks Nomad. That was an informative link you sent.
I will ask the printer about the settings.
Selwyn
Selwyn,
Should I use US Sheetfeed coated v2 or US Sheetfeed uncoated v2?<<
Depends whether you are having the job printed on coated or uncoated stock. Glossy is always coated, Matte may well be uncoated.
Web presses are used for newspaper and magazine printing and some other long-run printing. The ‘web’ is the paper once it comes off the roll, that ‘weaves’ its way through the press and eventually arrives at the cutter and folder printed both sides.
Len:
I emailed the printer who advised me to use coated.
Now I have to do alot of work readjusting some colors after I convert to CMYK. Then I have to re-import these converted files into Pagemaker where I have created complex multi-layer files. Then I have to hope my PDF settings are correct in Pagemaker, so my CMYK files stay CMYK and don’t convert back to RGB when I create PDFs.
Lots of work to do. And then I cross my fingers and hope the colors come out pretty close on the printer’s proof.
Lastly, I hope the public appreciates my work (visual mnemonic music education charts) when it finally gets out there. So please understand that all the help I am getting in this forum is serving the cause of helping people who are visual learners, learn music theory and therefore be encouraged to stick with their instruments and learn to play music.
Thanks, Selwyn
If you follow the philosphies of Adobe’s color theory, ideally you should be able to keep the file in RGB until the last step – the RIP. In the hands of a knowlegable operator with decent equipment, you will get prints that can be far outside of the gamut of SWOP.
Unfortunately this is a pipe dream because most printers couldnt tell you their color settings, let alone have a clue of what it is those settings actually do, let alone actually be confortable sending an RGB file to RIP.
Another problem with a true RGB workflow is the inability of having K only elements. Once a file goes from RGB>CMYK, the blacks get converted based on the profiles GCR/UCR settings, with no regard to whether or not your 6pt black text needs to be K only.
Good luck with the job, Selwyn
Thanks Jason. That was very informative.
Selwyn
