pdf colour resolution 1

[petermeachem]

Hope for some advice here. I'm producing pdf's from a jpg (32 bit cmyk) in a vb programme. Problem is that the pdf doesn't print the same colour as printing the jpg from Quark. It seems to be too blue, pale green comes out pale blue.
I'm not fiddling with anything here, load picture into picture box, write to pdf with jawspdf.
Can anyone give me a clue as to why this is happening. I'm totally foxed here and have no idea where the fault is.

http://www.accuflight.com

http://www.lettersdirect.co.uk

http://www.ourhouseinportugal.co.uk/

 

[tgreer]

Quark is probably outputting with either a color profile loaded, transfer functions, or both.



Thomas D. Greer

http://www.tgreer.com

Providing PostScript & PDF
Training, Development & Consulting

 

[petermeachem]

The jpg came from Quark via Photoshop. Do you mean that Quark is fiddling with the colours before printing? (talk about being out of my depth)

http://www.accuflight.com

http://www.lettersdirect.co.uk

http://www.ourhouseinportugal.co.uk/

 

[tgreer]

Peter,

I'm not clear on your two workflows. Maybe you could draw a little diagram for me?

Quark wouldn't fiddle with colors before printing, but during printing. When Quark sends the PostScript print stream to your printer, it can optionally send a color profile with the job.

A color profile is a way of making the colors of your image fit the gamut of your output device.

It could be Quark or Photoshop or both.

So diagram or describe your two methods, and also describe any settings or choices you make in the print dialogs or "save as" dialogs, etc.


Thomas D. Greer

http://www.tgreer.com

Providing PostScript & PDF
Training, Development & Consulting

 

[petermeachem]

Thomas, thanks again for your help. The other bloke was creating the jpg on a mac. This seemed to take an inordinate time, but he ended up with a jpg that printed ok from Quark with the colours he expected.
What I am doing is to take that jpg and print it to a pdf using jawspdf in a vb programme. I've just found some colour settings in Jaws, but haven't a clue what they mean.

http://www.lettersdirect.co.uk/jawspic.jpg

http://www.accuflight.com

http://www.lettersdirect.co.uk

http://www.ourhouseinportugal.co.uk/

 

[tgreer]

So at this point we need to compare the color/print settings in Quark on the Mac vs. the Jaws settings.

Transfer functions are a primitive sort of color management. They definitely alter the color, though. It's a way of saying "darken this a bit, lighten that" to your printer. So I would start by changing that setting to NOT apply transfer functions.

(Colors in PostScript are numbers or an array of numbers. For example, "1 0 0 setrgbcolor" is 100% red. A transfer function is just a mathematical formula to alter those numbers. It can, for example, turn all 1's into 0's and vice versa, so that your printer would print "negatives".)




Thomas D. Greer

http://www.tgreer.com

Providing PostScript & PDF
Training, Development & Consulting

 

[petermeachem]

Right, I'll ring the printer guy tomorrow and get him to have a fiddle with the jaws setting.

Thank you so much for your help.

http://www.accuflight.com

http://www.lettersdirect.co.uk

http://www.ourhouseinportugal.co.uk/