Why do they reject sRGB???

[kdw75]

I am by no means a color expert, but I do spend 40-50 hours a week dealing with customer supplied files and printing them to our digital presses. We regularly use RGB and sRGB files to print and they seem to give a slightly more vibrant colors when printed than CMYK FOGRA files do. I can't remember the last time we had any issues with them giving unexpected results. We also prefer PDF/X-4:2008 files. It seems like having a larger color space and then converting it down to what your printer can handle would be ideal rather than working with a color space that doesn't take full advantage of what the output device can do.

So why is it that so many of the trade printers we use for doing offset, flexo and inkjet work kick back any file that isn't CMYK and PDF/X:2001?

 

[Magnus59]

I am by no means a color expert, but I do spend 40-50 hours a week dealing with customer supplied files and printing them to our digital presses. We regularly use RGB and sRGB files to print and they seem to give a slightly more vibrant colors when printed than CMYK FOGRA files do. I can't remember the last time we had any issues with them giving unexpected results. We also prefer PDF/X-4:2008 files. It seems like having a larger color space and then converting it down to what your printer can handle would be ideal rather than working with a color space that doesn't take full advantage of what the output device can do.

So why is it that so many of the trade printers we use for doing offset, flexo and inkjet work kick back any file that isn't CMYK and PDF/X:2001?

I suspect a hangover from older rips, where you would either get a black & white image or a very dull & washed out CMYK conversion from an RGB image.
Brisque for example did a horrible conversion, basically mapping the RGB channels to CMY. Modern DFEs have ICC based conversion settings built in and do quite a reasonable job.
We still convert everything to a FOGRA standard whether it's being printed offset or digital, primarily so we can repurpose jobs as required.

 

[Macmann]

RGB works soooooo much better to large/wide/grande/inkjet printers. Customers are rarely savvy enough to convert to CMYK with the proper profile and the resulting conversion always falls flat. If we get to convert, at least we know what works best for us whether in Photoshop or at the DFE. ICC profile predictability and smaller files make RGB a no-brainer. RGB always looks snappier when printed. The same goes for leaving Pantone colors as spot color as well. It's amazing how close to the Pantone book a modern DFE can get to most Pantone colors.

 

[Joe]

So why is it that so many of the trade printers we use for doing offset, flexo and inkjet work kick back any file that isn't CMYK and PDF/X:2001?

Because 20 years ago someone told them to.

 

[Lorenzo lab guy]

We come at this from the opposite direction having started as a photolab. Additive color spaces are all we dealt with for years. On the rare occasion a CMYK file would sneak through our online or kiosk order systems our silver halide paper / wet processor printer would literally print the file with inverted colors. Once the two worlds started to both be widely used in our shop we had to implement some hard and fast rules. Most of the rules are no longer relevant but old habits die hard. Most of our RIPs can now deal with anything. Older photo printers really do perform better with sRGB or Adobe 1998 RGB files. Prophoto RGB doesn't work well with our very old wetlab (the conversion to the printer native sRGB wrecks the skintones), but is just fine with our modern large format or flatbed UV printers. Newer wetlabs can deal with a wide variety of colorspaces and profiles but many photolabs are going to ride an old quarter million dollar printer for a long time if they see a declining overall market for silver halide prints.

 

[Stephen Marsh]

In many cases they don't want to be held responsible for gamut mapping, forcing this back to the supplier of the file so that they are aware of and are responsible for any saturation and or hue shifts.

Edit: Forgot to mention, it is rare in my experience that a digital press is set up as a "full, native device gamut" – they are often set to simulate an offset press colour space, even if they are capable of a larger gamut. Spot colours are obviously a different story, where a lookup will likely be performed from a Lab based library direct to the full gamut of the device.

 

[Puch]

Accepting RGB or PDF/X-4 (and printing that without a proper approval cycle) might work until you run into a) a really wrecked material, b) an "expert" on color. I had the opportunity to meet both of them, and it wasn't a comfortable experience.

RGB colors can be way more saturated what your (properly set up) digital printer can print. The "color expert" might accept that or not, but I found out that the easiest way to deal with them is to make CMYK submission obligatory. This way the RGB-CMYK conversion happens at the customer's domain, and I don't have to argue my ass off about color management basics.

The situation is similar with PDF/X-4. You don't know what software was used to create the material submitted, moreover, you don't have any knowledge about what software was used to check the data in the customer's approval cycle. Why should I take responsibility for a leaflet which was created with an online solution by some amateur, then checked and approved by another amateur on a mobile phone screen? I'm still more confident printing flattened CMYK documents.

 

[mrserge]

1. You are not running 10 years old RIP
2. You know what color management is
3. You know how to handle random color space graphics that customer can provide and have a backup plan for edge-cases

If answer to all 3 of these is Yes, then you shouldn't care about the input color spaces.
But judging from the question, you don't know how dangerous random RGB profiles can be. So in your case I would at least stay with requirements to provide sRGB graphics and make a rule that any RGB objects with or without defined color space would be assigned to sRGB.

 

[chriscozi]

3. You know how to handle random color space graphics that customer can provide and have a backup plan for edge-cases

But judging from the question, you don't know how dangerous random RGB profiles can be.

Ran into this once full steam a couple of years ago.
Turns out the engineer (customer) had changed all the default color settings on every computer in their business to get the output he wanted on their low end plotter.
When he provided the documents (PDF) to us and we physical proofed it back he was underwhelmed.
After a back and forth we finally got the story of the color space.
He was frustrated that a 'commercial printer' couldn't make things look the way he wanted even though he refused to provide a printed color sample (at first.)
We then matched the color on the provided sample in CMYK and he said 'not good enough.'
We explained that color gamut was an issue because of the starting color space and he went away saying 'I'll just keep printing them on our plotter and I'll get the color I want.'
We were happy to oblige.

 

[bcr]

found this thread interesting.
i'm just starting to print more colour sensitive jobs and my knowledge of colour and pdf standards is almost non-existent.

could anyone recommend any beginner's reading materials to get to grips with this type of stuff?

 

[Ferran]

found this thread interesting.
i'm just starting to print more colour sensitive jobs and my knowledge of colour and pdf standards is almost non-existent.

could anyone recommend any beginner's reading materials to get to grips with this type of stuff?

Hi bcr,
I would suggest to anyone involved in prepress that should visit the Ghent Workgroup website. There you can find a lot of resources and documentation. You can download the PDF/X Workflow documentation based on the GWG2015 specification. The GWG has also published recommended applications settings for the most common used applications. It is important to mention that there are settings for PDF export but also for PDF validation (preflight). By the way, you will see there are different variants, so you can decide if you prefer the “CMYK workflow” or the “CMYK+RGB workflow”, both are based on the PDF/X-4 standard. And you can also test your workflow with the Ghent PDF Output Suite.

As I said there is a lot to see, included some recorded webinars that cover many topics, and more ...

Enjoy, have fun!

 

[Lorenzo lab guy]

found this thread interesting.
i'm just starting to print more colour sensitive jobs and my knowledge of colour and pdf standards is almost non-existent.

could anyone recommend any beginner's reading materials to get to grips with this type of stuff?

bcr:
If you really want to understand color work at a basic level, especially when working with photos, I highly recommend Margulis book, it is really the standard in the photo business:Professional Photoshop

You will understand theory well enough after mastering this to solve many problems. It is not really a book about printing but more about working with color on images. I used this to train quite a few folks in our photo lab. My favorite bits are (1) using the unwanted color to make an image appear sharper, and (2) training a colorblind person to do color correction in photoshop.

 

[bcr]

thank you both!