Colorspace selection sRGB or Adobe RGB?

[bobbyrab]

Rich thank you for taking the time to explain colour management in such a clear and concise manner. I hope you don't mind if I could trouble you with a related problem of my own.
I've done a few advertising campaigns that run as full and double page spreads in national glossy wedding magazines. I supply the client with three versions of the files, 16bit Adobe tiffs, 16bit CMYK tiffs, and 8bit sRGB jpegs. They then give these files to their graphic designer who designs the layout, then provides this to the magazines as a PDF with the image inserted in the PDF.
When I convert the Adobe RGB file to CMYK, I make an adjustment to the black point as they will often lose contrast in the conversion.
The problem is the mixed results we get in the published advert, generally Condé Nast titles will be fine, but other publishers can look like they've lost the black point adjustment so they'll sometimes look flat and dull.
We have tried having the CMYK files as test prints and they look great, only for the printed adverts to still be patchy.
I know Condé Nast were very particular about what type of CMYK file they wanted as it seems there are a few different standards, and I'm wondering if the graphic designer is supplying the magazines with the Adobe file and leaving the publisher to make the conversion to CMYK, some making a better job than others.
Any ideas of where I'm going wrong would be greatfully received. Thanks....Robert

 

[kbg32]

Horses for courses. What ever floats your boat.

http://www.luminous-landscape.com/tutorials/prophoto-rgb.shtml

http://www.outbackphoto.com/color_management/cm_06/essay.html

 

[RichC]

I've done a few advertising campaigns that run as full and double page spreads in national glossy wedding magazines. I supply the client with three versions of the files, 16bit Adobe tiffs, 16bit CMYK tiffs, and 8bit sRGB jpegs. They then give these files to their graphic designer who designs the layout, then provides this to the magazines as a PDF with the image inserted in the PDF.

When I convert the Adobe RGB file to CMYK, I make an adjustment to the black point as they will often lose contrast in the conversion.
The problem is the mixed results we get in the published advert, generally Condé Nast titles will be fine, but other publishers can look like they've lost the black point adjustment so they'll sometimes look flat and dull.

We have tried having the CMYK files as test prints and they look great, only for the printed adverts to still be patchy.

If you supply a client with a photo that's been optimised to how you and the client want it to appear - and (a) you've done this on colour-calibrated screen so you're in full control of the colour (which from your description I expect you do), (b) you've embedded a colour profile and (c) there's a covering note to the designer pointing out not to change the photo (don't mess with the colour or curves!) and that there's a profile embedded, then the photo should print similarly to how you expect.

CMYK always looks a bit flat compared with RGB - as I'm sure you're well aware when you convert! Offset printing makes the photo look even crapper!

Anyway, if you and the designer are happy with the appearance of the photo, then I don't think you are doing anything wrong: it sounds like the printers are not doing a good job, especially if the press proofs look fine.

You can do a few things to optimise the CMYK conversion:

• Tweak the colour after conversion: bright greens and oranges tend to dullness, and dark blues can end up mauve.
• Adjust the contrast to compensate for the reduced colour gamut. Do keep an eye out for blown highlights and blocked shadows - especially if they involve the above colours.
• Compensate for dot gain - ink spread during the offset printing process that makes halftones print less contrasty and saturated than expected: 15% is a good figure for modern presses.*
• Embed the correct profile. The modern European standard is FOGR39*

* Ideally, someone should talk to the printer (you, the client or the designer) to find out what they require in an optimised CMYK image - they will have their own preferences for dot gain (which will vary with paper type) and colour profile (though many clients are too inept to sort this out or give you permission to liaise with the printer, so you may find yourself using the above "defaults"!). It's uncommon today to supply photos as separate files to a printer, but a very few may still prefer this so they can process the images themselves - extremely unlikely to happen with ads - typically, the designer will sling a PDF of the entire mag including the ads at the printer.

Also, talk to the designer to see what they want: chances are they'll be perfectly happy with a single TIF file - that converted to CMYK. Providing unnecessary files simply causes confusion.

Only 8-bit files are needed in books/magazine production, so you forget about 16-bit (overkill - I can guarantee that the designer converts your 16-bit files to 8 bit as soon as they get them!). Also, unless the client specifically wants Adobe RGB TIFs, I'd provide sRGB instead (Adobe RGB is pretty much ignored in publishing) - this RGB file may still be wanted in addition the CMYK file, as the ad may be repurposed (e.g. website, online PDF, email), and it's better to use the RGB file than to reconvert the CMYK file back to RGB. The JPG is also possibly still useful, simply because of its much smaller file size and ability to be viewed in pretty much anything (so, useful for the client - not so much for the designer). Talk to the client, and see which file(s) they need, and only send those which are actually going to be used.

If it's really important to get the contrast and colours right, then the client should confirm with the printer that the printed copy will match the press proof. Note that the press proof won't be a "pull" from the press itself but is likely to a laser proof using the designer's PDF that's been fed into the printer's RIP. That said, if a printer supplies a proof, the least they can do is ensure that it is an accurate reflection of their offset press - so, if the published ad differs, I think it's reasonable for the client to moan at the printer!

As a last resort,you can always supply the client a physical print of the photo, the sent to the printer so they can match the appearance.

 

[fotomeow]

lots of great in-depth info here: thanks guys.

I just wanted to offer perhaps a simpler explanation for people like myself who are not a a pro in the field.
I was taught to use Adobe rather than sRGB, for the above reasons, with the simple
reminder that sRGB stands for "sh*tty" RGB.
But remember you can, with many modern digitals, tell the camera to save RAW and JPEGs simultaneously.
you may not be ready to convert RAWs right now, but may want
to have RAWs for future conversion, when I/we/you have proper RAW converters on your computer,
to convert in the future.

E.g: if you are taking some meaningful pics (family, friends, wedding, travel) shoot the RAW & JPEG.
the jpegs are for quick prints for the web and giving to others. keep the RAWs for when you are ready
to go back and fine tune the pic for blow ups, submission to magazines, contests, etc.
Its not much different than shooting film negatives, where you can get the quick 4x6" prints for immediate use,
and still have the negative as your "RAW", high-quality template.

 

[bobbyrab]

Thanks again Rich, that's much appreciated....R

 

[Ranchu]

I'm a better photographer than 99% of the M9 owners here

And you're not even that good!