rgb workflows

[motormount]

I'd like to ask what traditional (not digital) offset printshops do with file preparation and color management.

Firstly if you accept native files - that's the ''easy'' part, if a printer has the infrastructure to work reliably with native files, then color manipulating/managing these files should be no problem to him, but then are you working in rgb mode letting the rip doing the separation or you work in cmyk inside the application giving the rip a cmyk tagged file?

Secondly, -and probably most commonly- in strictly pdf workflows if you color manage files,if you accept pdfx3-4 files etc.

(Here files are processed based on their cmyk percentages irrelevant of their profiles -if they have any-,and only time when color conversion takes place is when a job has to much ink for our old press to handle, where i use some ''ink save'' device link profile to drop down ink total.

If files contain non cmyk data,customer get's warned either sends files back or tell us to do the conversion ourselves and same as above then.)

Even though i read a lot about rgb workflows and late in rip separations scenarios, my real world experience doesn't provide me with lots examples of shops color managing their files - to be honest none, except from cases i read in the internet.

I'm writing again that i'm mainly interest on offset printshops, not digital printers and if it is possible i'd like to hear some small description of the shop - if i get all answers from people in big shops-plants with 4-5 prepress operators and inhouse IT departments things should be very different from the average medium printshop with one man show prepress workers doing anything from customer service to postpress chores-.

Every answer is valuable,thank all in advance!

ps I posted same question on print planet,interest in prepress is waning as Laurens from prepressure noted and every single answer is valuable like i wrote.
If there is any kind of problem with that, please notify me!
Thanks again!

[Joe]

We have 4 web heatset offset presses with a fifth on the way in August. 11 prepress people that also server as CSR's (not officially but we don't have official CSR's so we're kind of stuck with it).

We encourage customers to use the PDF/X-4 standard if possible only changing the compression from the default JPEG to ZIP. This PDF setting does not do any type of color conversion so the resulting PDF has everything in it from RGB to CMYK to LAB including spots. Our customers upload their files through Kodak Insite Prepress Portal where the files are refined immediately and everything is converted to CMYK during the refine process which are then in Insite where the customers view the pages in Kodak Smart Review. There they can check bleed, trim, separations, and the preflight report generated during refine. The customers then either reject or approve the pages. If they reject any they then send new file(s). Usually if we have to fix anything we work on the Prinergy refined PDF but there are times we have to go back to the original. We get almost no native files anymore and strongly encourage customers to send PDF's.

[andyfest]

We have two Heidy Speedmaster offset presses here - a 29 inch 6 colour and a 40 inch 7 colour. Our Nexus workflows are set up to red flag  any RGB images they encounter. Almost all of the client files coming in are supplied as Illustrator files with supplemental PhShop files. Once in a blue moon we get an InDesign file or a "press-ready" (ha!) pdf.  We work CMYK-mode only, but for the most part our clients are pretty good about using the correct colour mode.

[motormount]

ok Joe thanks for your quick answer!

A much better workflow than mine,i either fix the pdfs with pitstop or heidelberg tools, or in more complex cases i call the designers and guide them...

One more thing,rgb's turn to cmyk with some perceptual rendering intent i suppose but could you tell me about cmyks:

Do you perform cmyk to cmyk convertions based on file profiles or you just keep to the cmyk numbers of the image/elements of the pdf?

Andy thank you too,that's a ''classic'' kind of workflow right?
Anyway, no late conversion workflows till now!

Thanks both!

[Joe]

Do you perform cmyk to cmyk convertions based on file profiles or you just keep to the cmyk numbers of the image/elements of the pdf?

No CMYK ===> CMYK conversions. If something is already CMYK Prinergy leaves it as is.

[motormount]

(same thing here - and every printshop i know of)

So i got two answers, twice as better than printplanet where i got none!

 You can't really jump to any conclusion judging from two answers on the internet and the few printshops you might know yourself out of the thousands that print any kind of job every day, but still where are those people/shops who works in rgb mode to take advantage of the greater gamut and let the rip do the separation?

 Like the color experts advice things should be done?

 Anyway,thanks again for your time answering!

[Ear]

Mine is similar to Joe. I'm running Xenith Sierra (XMF rebadge) and it is a CMYK workflow, because I am an offset shop. RGB images are converted to CMYK with an action embedded in the preflight. No CMYK ==> CMYK here either and I don't honor embedded profiles. I have plate profiles for the fingerprinted presses but all files are otherwise run as is.

I don't see the point in leaving something RGB until the finishing stage. You can't print in RGB, might as well convert it right up front so you can see what your end result is, as opposed to being unpleasantly surprised at a later stage.