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Photography Question 
Beverly Burke
BetterPhoto Member
bevburkephotography.com

member since: 4/18/2004
 

Printing with CMYK


I have been asked to work on a project with a graphic designer. I have taken images that will be sent for printing to a company that prints in CMYK. I work on images in Photoshop in Adobe RGB. Should I now convert these saved RGB images to CMYK prior to sending them on disc to the designer? Or do I have to start from the beginning working on them in PS as CMYK images? Help appreciated!!

8/18/2009 3:15:14 PM

 
Richard Lynch
BetterPhoto Member
PhotoshopCS.com
Richard's Photo Courses:
4-Week Short Course: Correcting and Enhancing Images
4-Week Short Course: Looking Good in Print and On the Web: Color Management
  Ask the designer what they want. Generally, you will correct in RGB...and sometimes make small CMYK adjustments but only if you really know what you are doing. With workflows and processes as they are now, you can likely just submit RGB files ... but check with the designer.

8/20/2009 10:48:53 AM

 
Roy Blinston
BetterPhoto Member

member since: 1/4/2005
  I agree - check with the designer. However I am also a graphic designer and, after careful thought on this subject, one could go either way (as there there are pitfalls for both).
CMYK printing is what the print industry and your desktop printer uses. If you have never converted a file from RGB to CMYK then best leave it to the designer.
It's not difficult to do (not at all) but one has to have some experience in this area, especially regarding "dot gain" and colour differences when you switch from one to the other.
Try it with a "sample print" yourself. Have your RGB file ready on screen, study it carefully, then switch it to CMYK TIF. You will immediately notice a colour difference. This is because RGB is "video colour" (light) and CMYK is an "ink". Saturation especially will show a noticeable difference when switched to CMYK. This is unavoidable, so don't panic.
"Dot gain" (ink squash) is what happens on the Press. There are 4 printing plates (C, M, Y, K) and each plate will suffer varying degrees of ink squash (depending on the ink coverage of your photo/pic)... hence it is unavoidable that a picture will change slightly after being printed.
Every print machine suffers a different amount of "dot gain" (especially older Presses) but good quality control by the Print House will usually yield somewhere between 3 to 8% for each plate.
As I said... if in doubt, leave it to the designer.

8/25/2009 3:49:03 AM

 
Beverly Burke
BetterPhoto Member
bevburkephotography.com

member since: 4/18/2004
  Thanks Roy and Richard. After reading your reply, I did speak with both the designer and the printer. It was decided that I leave the files as RGB and the designer and printer will both work together to color proof the finished product. Apparently, after consulting with the designer, there is much trial and error and adjusting with this process. Thanks again.

8/25/2009 5:43:48 AM

 
Kathy Wesserling
BetterPhoto Member
Contact Kathy
Kathy's Gallery

member since: 4/21/2005
  As an ex-printer, here are a couple of things for you and the artist to keep in mind. Black and Red next to each other are seen by the old Printer's cameras as Black, period! Also, when images and text are reduced from the original artwork to the printable plates or files (for brochures, etc), drawn lines and spaces also reduce. Anything that is teeny and/or close can 'disappear'.

This info is based on the old ways, but still may be important to consider, depending on the equipment used by the Printing Company.

Artists used to make my Dad break out in a rash! lolllllllll

8/25/2009 6:55:42 AM

 
Roy Blinston
BetterPhoto Member

member since: 1/4/2005
  To Beverly: Good idea to leave it to your designer or print man. They have done this many times before. And yes it can be tricky trying to maintain original colour authenticity when switching from RGB to CMYK colour modes. Some shades/tones in RGB are impossible to reproduce using CMYK ink. All they can do is the nearest they can.

From past experience the truest colour rendition (with very little variation) is when you output your RGB picture files to an LED printer because LED's use "light" (to expose onto the paper) and not "ink" (to print onto the paper).

Also... all professional print shops WARN clients that colour variations will and can occur even with the same files being re-printed at a later date. Such are the mechanics of offset printing, even though remarkable progress has been made over the last 10-20 years in this field.

Per Kathy comment... what you say is true, but those days are long gone as the darkroom camera (for shooting artwork onto bromides and negs) does not really exist any more. Black & Red did appear as BLACK for sure. Your comment also reminds me of the "non repro blue pens" we used to use (ie: blue being invisible on industrial darkroom cameras). These were the days of "paste-up" (long gone).

Per your reference to "thin lines" (on artwork) something that many artists do (or draw in pencil etc) are age old problems that still exist to some extent. However neither of these things refer to what Beverly originally asked. Interesting comments though.

8/25/2009 8:35:27 AM

 
Roy Blinston
BetterPhoto Member

member since: 1/4/2005
  Just to open up a can-of-worms... I have seen hundreds of colour variations of famous paintings (like the Mona Lisa) even though they were photographed with meticulous care, and printed on very high quality Print Presses by people with years' of experience.

Some of this could be intentional as many old paintings, due to their age, can be quite dull and the Pre-Press Manager may intentionally liven it up for better reproduction... and not stay true to the original. Call it poetic licence (to sell magazines).

On the other hand if it is not intentional I still guarantee that 10 different quality Print Shops will render the same painting differently in their final production. This is a fact of life in the industry. Some will be very close, but they will all differ in some respects, especially if they are not printed on the same paper stock. There are too many variables involved.

8/25/2009 8:57:34 AM

 
Richard Lynch
BetterPhoto Member
PhotoshopCS.com
Richard's Photo Courses:
4-Week Short Course: Correcting and Enhancing Images
4-Week Short Course: Looking Good in Print and On the Web: Color Management
  If you end up doing a lot of this stuff it will help to get to understand CMYK separations and what actually goes on digitally -- and also to talk directly with print services about what THEY prefer at the press (instead of what the artist in-between may interpret). Settings for gain are only the beginning. Combining the old methods of separation with digital, I came up with a custom CMYK separation that Elements users can use (everyone was saying that Elements couldn't do CMYK, so I wanted to prove that wrong). If you can find a copy of my Hidden Power book for Elements 4 or Photoshop CS (which has a lot of print info for PS users), you can learn a lot about what goes on to convert the images to print.

Roy, "true to the original" may have different interpretations ;-)

Richard Lynch

8/25/2009 10:13:47 AM

 
Roy Blinston
BetterPhoto Member

member since: 1/4/2005
  Please explain more, I'm not sure what you mean.

8/25/2009 1:55:00 PM

 

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