Preserved Topic: Colours....

Just when i thought i was getting somewhere, there comes another hurdle.. colours.

I do my business card backround in photo shop, its about the colour i want, then i print it on my desktop printer, looks good there too.

Now i decide to start doing things in illustrator so i can save as eps then convert to PDF with distiller.
But the colours looks different , i got it too look ok in illustrator, and print to similar to what im wanted, then i converted to pdf.

Now the blue is much brighter then i wanted!

Could someone please give me some tips, is there anyway i can know what the colour will actually look like when i get it printed properly?
Am i doing something wrong?

I'm not really sure the best way to go about this, some explaination would be great (stuart save me!)

Thanks in advance all

to elaborate a bit, i do know some things, like that the RGB range give more colours then you can actually print with CMYK.

If i'm in photoshop or something and start a cmyk document, are all the colours that i CAN pick colours that you can print? or does it allow an entire range of colours, even those that i cant print the same, also is there any way to know WHICH colours WIll come out the same?

Few things like that are confusing me ;( .. yet again.

Basicly the advantage of working in CYMK is there should be no colors you could not print with CYMK profile you have choosen. If for instance, we pick "US WEB Coated SWOP v2" and you print the document in a workflow calibrated to the SWOP standard. All the colors specified should be reproduced. Other do have an effect but reproduction should be close.

There are color however that are not adviseable to print, such as those over the total ink coverage advised for the press often between 280-320%. Totals over this values cause problem on press such as stripping, smearing, and poor drying. Total ink coverage or Max denisty is the total of an eye dropper reading of 100c 100m 100y 100k would equal 400%. Far to much ink for the press and paper. If I have a total density of about 320 on press, my darkest shadow density should not be higher then (95c 85m 85y 55k)

Now if you are converting an image from RGB you shouldn't have to worry about it, the limits are built into the profiles, It is important to remeber as you can set unprintable colors colors when produce artwork in illustrator and photoshop. Photoshop and Illustrator will warn you of out of gamut colors but will not warn you about total density problems.

You may have noticeed the values, (95c 85m 85y 55k) process inks are far from pure and the compensation for this is called the gray balance. Which differs for each workflow and changes at density levels thou the ratio is similar. Basicly the same principle behind profiles, it what we color control specialist did before profiles existed. In my workflow this ratio produces a nice neutral looking blackand grays. One can find the gray balance for a choosen profile, by creating a color ramp in 0-255 in R,G, and B and convert it to CYMK using your choosen profile. Then sample the value for the choosen density level. This should allow you to specify neutral grays/black for print using the profile. Becareful the world is far from perfect and unexpected results will come into play at the imagesetter and press.

Other problems occur when printing to other devices not calibrated to your profile. When the happens you must either convert to the new profile, retouch the images, or print using a profile where it is translate it to the new devices color space.

More potental problem. My guess is you are sending it to a Consumer level inkjet. One designed to except RGB data, which is then converted to CYMK or CcYMmK by the print driver. This can cause some problem when sending CYMK data to the driver. Depending on the driver it is could be converted to CYMK--->RGB--->CYMK which sometime can cause some odditys.

You might try setting you output space profile to the profile for your printer. That way the application will perform the convertion on the fly as it sends the data to the printer. For instance I have a Deskjet 1120c, so I set my output profile to the HP Colorsmart Driver. My document is CYMK but when I print it is converted using this profile and then fed to the printer. The document stay CYMK just the print data is changed.

Just keep in mind most consumer inkjets prints are poor indicators how the job will run on press. Unless you have the ability to keep it calibrated I wouldn't trust it for proofing color. Most Inkjets also are far to sensitive to temp and humity. Even the calibrated Digitial Matchprints (Inkjet proofs) I have used can jump up 5% for every 2 degrees over there optmum operating enviroment.

For choosing color I would trust the numbers. I suggest a Getting a Pantone Process Color Guide a Trumatch Process Guide or a Process Color Table Guide for picking colors and hope you can trust the number on press. Use the consumer inkjet to find stupid color mistakes or ruff color, if color is critical I would have the printer do a proof that they trust and will sign off on. Thou this can get expensive, the proofs I get are about $50us for super tabloid (13x19).

The best advice I can offer you make sure you have your color profiles set-up correctly.

1. First Calibrate your monitor, I just use Adobe Gamma, I have heard that it will not function on LCD monitors however.
2. The set your color profile controls for Photoshop an save and name your settings.
3. Now load Illustrator, and load the photoshop profile setting into is color manangement.
4. Do the same for InDesign.

Lucky Illustrator 10, Photoshop 7, and InDesign 2 all share the same color management engine. So you can load the same setting into all of them. Now you should beable to spec color in each with out problems.

Addtional problems can accure when exporting and and distilling to PDF. Here color profiles can profile convertion be specfied as well. I wound set it to leave unchanged or none and I would not embed profiles. Most of my printers do not use profiles in their CYMK workflows. THis may very and it's best to find out what the printer desires first. The setting become much more important if you are working in a dynamic color enviroment one where you work all images etc... in RGB and then target the PDF for each output device or target

I hope to do some research on Acrobat's color profile setting. I need a bit of a refresher. If I find any good sites I will post them here.

J. Stuart J.



[This message has been edited by jstuartj (edited 09-12-2003).]

Thanks stuart, explains a fews things =/ ill have to find somewhere to get hold of one of those charts. Myabe my printer has some.

For my current publisher i dont have much control over the settings for distilling to a pdf, they have a file suited to them that we download and use that profile to distill. Im not sure if this process however is effected by any different colour profiles i have setup in the EPS file in Illustrator, i might have to ask them about it =/..

Luckily they are pretty cheap with proofs, so i might get them done, about $15 US for an A4 i think, tho im not sure if thats a full on proof or something else.

Thanks again, ill see how it goes =/