RGB vs. CMYK

Hi gals and guys,

Was looking at entering a land based photo comp.........and the comp. specifies that all photos have to be submitted in CMYK format.

Basically

1. What are the advantages? I mean...does anyone here use this format???

2. I take it you can only convert RGB files to CYMK format using CS3? (I cant do it using elements 6.0)?

Thanking you all for any insights in advance

Damo

That is truly bizarre (the convert to CMYK). The only reason I can think of to do this would be if a large percentage of the submissions were going to be printed in a book or magazine. Maybe the people who run it are lazy and want you to do the CMYK conversion for them. But this would be strange, though, because you'd need to know what kind of CMYK to use, and most people aren't experts at conversion for print, so they'd be likely to get a bunch of crap, anyway.

Another option: the competition people have no idea what they are doing!

I vote for the second option.

Alex

Or they hope that everyone joining knows what they are doing! Did they supply an ICC profile? And are Eric and Alex right?

Or they hope that everyone joining knows what they are doing! Did they supply an ICC profile? And are Eric and Alex right?

Hi Drew,

Eric and Alex are always right

Aw.....ok.......u r too Drew!

Actually- to clarify a bit- this particular competition was run a few months ago on the Irish Photography federation website...http://www.irishphoto.ie/ ...

I have been trying to find the link to show you the actually entry form........ but I think its gone as the competition date has expired...

I'll keep an eye out tho' in future....just so you can see..

I just remembered that part of the condition of entry was to submit the entires in this CMYK format...which I thought was odd....I never heard of CMYK format...and was just wondering what the big deal was?

Thanks to your collective wisdoms...prt. you Eric- yes-I think the winning entries were going to be published in a book.

My question today was piqued out of curiosity....and as usual....I get my answers without fail.

tanx boyz

A monitor makes colour by adding light from three sources Red, Green and Blue. Paper printing makes colour by starting with white paper and subtracting colour by adding inks in Cyan (minus Red) Magenta (minus Green) Yellow (minus Blue) and Black (K) (minus light). A lot of pictures look great as additive colour RGB on the monitor but go wrong when printed in the subtractive format (ie on white paper with ink). Maybe they wanted to avoid the pitfall of choosing a great shot then finding it didn't print well.

I guess they could always go back and ask the winners for original files and then do the conversions. I know that when DYK magazine in Scandinavia puts in its parameters to files sent to it by DIVER mag, they get much better repro and presumably the files are all CMYK when they get them.

A monitor makes colour by adding light from three sources Red, Green and Blue. Paper printing makes colour by starting with white paper and subtracting colour by adding inks in Cyan (minus Red) Magenta (minus Green) Yellow (minus Blue) and Black (K) (minus light). A lot of pictures look great as additive colour RGB on the monitor but go wrong when printed in the subtractive format (ie on white paper with ink). Maybe they wanted to avoid the pitfall of choosing a great shot then finding it didn't print well.

 

I guess they could always go back and ask the winners for original files and then do the conversions. I know that when DYK magazine in Scandinavia puts in its parameters to files sent to it by DIVER mag, they get much better repro and presumably the files are all CMYK when they get them.

As a professional dealing with my images being used exclusively in printed matter, I can tell you with a considerable measure of certainty that whoever asks amateurs (regardless of how nice the images are) for CMYK conversions does not know what they are doing. I would run, not walk away.

The correct color space for web/emailed images is currently sRGB. Photoshop and most cameras come with sRGB as the native color space...sRGB is also one of the smallest color spaces. Anyone using camera RAW files and adjusting on a computer would be well advised to make the preferance change within Photoshop to a wider color space...ProPhoto or Adobe1998 for example. If you enter a contest online, sRGB is what you should use. Adobe1998 offers more color, but will get clipped when used for email or web presentation. CMYK is strickly a printers color space...and I do not mean your desktop Epson, HP or similiar...CMYK is for commercial printers. Normally the printer will accept your image file and make the conversion of the file using their own printers characteristic. If you want to make the CMYK conversion you MUST get the info from the printer and know what printer the final will be printed on. You also are accepting the responsibility for the color at that point...so don't complain. This all gets very technical very fast as you can imagine...Photoshop offers a conversion utility that is very good, but you need to understand how to use profile selection, soft proofing and out of gamut display. Thus...not something most amateurs want to spend the time investigating. Colormatch RGB comes pretty close to approximating the look of CMYK...but not exact. Best way to have some assurance, not 100%, that your image will be printed as you want is to include a proof print...a hard paper copy that you like...so the guy standing at the press knows that that starfish really is blue and not pink. You can have a "contract proof" made locally from your file to send along if the repro is really important and the color needs to be exact...expect to spend $100 plus for the proof. Call a local printer with questions about how to go about this if you have the need and the money.

Larry Gatz

I vote for the second option.

 

Alex

I'll second that!

A similar query has been discussed on wetpixel before and I'm pretty sure that the consensus then was the same.