CHROMiX

Standards for large-format/inkjet

My company is currently preparing to implement more formal process-control over our printers (all large-format inkjets, aqueous roll-to-roll, and UV flatbed), and I have been put more or less in charge of the project. One of the biggest issues I’ve come up against is the fact that there don’t seem to be any standards that are suitable for this type of printing. Does anyone know of any process standards for inkjet printing? Has anyone tried applying G7 or some other process to inkjets? Would a G7 expert care to comment on the feasibility of this?

Thanks

I am not a G7 expert but I’ll try to respond since I have put a lot of thought into this as of late. I believe that you can certainly adapt part of the G7 methodology to achieve common neutrality. I have succeded in aplying G7 neutrality to a grand format solvent printer at my location but the calibration still needed icc profiles to achieve good color overall. This is probably due to the colors of primary inks and media.

When you create good calibrations, ink limits and icc profiles you can more or less choose a standard by changing your input file to match that standard. With inkjets your printer profile will more than likely have a larger gammut than any of the CMYK print standards. You should be able to get a decent match for any. If you really want to see what the printer is truly capable of, you can try RGB. Unfortunately, most artwork is still created in cmyk so getting true RGB files is somewhat problematic.

Just my two-cents. I hope this answers more questions than it creates.

Robert

Thanks Robert.
The more I delve into the G7 howto, the more I see how we would apply it to our machines. Basically we just treat everything as a proofer. The problem we run into is that only a few of our machines (the encads) do a very good job of encompassing the GRACoL or SWOP spaces. I think no matter what, we’re going to have to come up with a fairly customized in-house standard. I do plan on experimenting with G7 as a replacement for Onyx’s calibration method, if for no other reason than G7 seems a bit more clear about it’s aim points and how to get to them.

Unfortunately you are somewhat at the mercy of the RIPs and profiling applications that support your devices. Standardizing on the same RIP and profiling software when possible helps a lot. Lab based linearization, when available, goes a long way too.

Scott Martin
www.on-sight.com

This is how most print-shops with your kit and customer type operate:
The standard used is the icc - usually the shop standardises with a single RIP running all the hardware. With your kit it is usually Onyx but not always. All printers are profiled using the RIP and sometimes other icc generation software eg Monaco. They are profiled for maximum gamut - each printer producing the widest gamut possible, to icc standards. Your output will be different from each printer, but correct and optimised in their own right. Jobs are sent to the most appropriate printer for the application & the printer will produce a neutral print with the maximum gamut it is capable of assuming you’ve done a good job with the profile.
However, if you want to produce exactly the same colour from different devices - so that your colour is “standardised” accross your company, then you must enter the world of proofing. Take the printer with the smallest gamut - this will be the gamut you standardise on. All your other devices will have to use the output profile for this small gamut printer/press as a simulation or proof profile in their own workflows. This “proof” profile sits on top of the existing maximum gamut workflow and narrows it down to match the printer with the smallest gamut, thus standardising the colour accross all the devices.
If you want to profile to SWOP just nail the ink restrictions in Onyx to the SWOP densities & finish the profile. If one of your printers can’t achieve this, you can’t use the standard. Thus those that do this just use the maximum gamut of their lowest gamut printer to standardise on.
As an aside, SWOP and the others are pre-press standards shoe-horned in to an inkjet workflow. They don’t really belong there and are not optimised for inkjet in the first place.
As you can see this may not be the best outcome as you are sacrificing gamut for a standard colour output accross all the devices. Proofing houses and much of the info you get when investigating these issues is pretty hell-bent on “standardising” when your customer base really doesn’t care. Most want “optimised” prints, rather than “standardised” prints and thus most colour houses will not kill the gamut unless there is a really good reason. Your competiton will provide high gamuts and saturated eye-catching prints - if you get too caught up with standardising you may lose track of what is really important - repeat business.
Just my 2 cents!