Help me match my iGen to an offset press!

[mbrennan5]

Ok, heres my scenario:
We reprint covers for case bound books, that were orginally produced offset. Our prepress is given quark files, which they run through Prinergy, and we print them on the iGen as PDF's. Im dont think any color adjustment is done in Prinergy, and we run them as CMYK swop_plus / relative colormetric on the iGen. This workflow is accurate about 60% of the time. Other times we adjust the rendering intents, add a TRC, or just produce it as is. I have been keeping a record of what settings we use for what covers, but we are getting to the point where there are too many to keep track of.

Heres the problem: I dont have access to the offset press. These were originally printed at a competitors facility. Is there any way to create a profile to emulate what they are producing? I have access to offset and proofing equipment here, just not the actual press they ran on.
Thanks
Matt

[TigerPress]

Unfortunately you are probably chasing a moving target. It is likeley that not all the covers were printed under the same press conditions and many were probably altered (on press) at the request of the customer.

Without having a profile for the exact press, I'd say you are doing the right thing - just need to adjust as needed.

[trzmielina]

What is the minimum delta E variation for the iGen, hardware-wise.

I know that delta E's don't tell much, but my point is to mention that you are not dealing with a very stable device as far as color consistecy goes to begin with... add uncontrolable variables from the off-set side (since you do not have them) and it will be, as mentioned before, literally a moving target.

You can try profiling the iGen and the off-set presses (you would need to have them run targets for you and either you profile an average of 20 targets or pick the one you want to "match").

Find out from Xerox of the iGen is capable of holding... Can you let me know? I am curious.

The thing here is to educate the market that once you move to POD you value proposition changes. Perfect color matching to off-sets should not be the goal for iGens or Nexpresses (maybe not even Indigos), they belong to a different market layer. The added value to POD is time to market, varibale data support, and lower break even as far as cost per unit... Can we sell this? Tough call...

Ricardo Trzmielina

[LoganBlade]

www.gracol.com

look here

[mbrennan5]

Im unsure of the deltaE for the press. Xerox does distribute a chart showing acceptable color drift within run, so I understand realistic expectations. I was just trying to think of a way to create a generic profile to emulate the press that I cant actually profile. Is that where the Gracol suggestion comes in? Right now we just switch our renderings between iGen CMYK, SWOP Plus, SWOP Coated, and Commercial CMYK and then make additional adjustments via TRC.

Please understand that our standards for "matching" are pretty low as our customers understand our service to them. I'm talking color differences that are obvious without measuring or magnification. I'm just trying to come up with an adjustment to our current workflow, or an additional setting to try on the press, that will help us match a higher percentage of jobs without manual intervention.

Our digital operator mentioned that all files are converted to CMYK in Prinergy including PMS colors. His thought is that if the color is indeed inaccurate on press, the spot colors would be off anyways.

Right now I use the output preview tool in Acrobat to help me get a feel for the SWOP CMYK makeup of the file I am working with. My next tool in that line of thinking will be a Pantone Digital Chip Book which will allow me to compare the offset sample to the swatch and its digital CMYK equivalents, but again I am still taking up alot of my time, and as our business grows, I will need to simplify the process.

[we3dumys]

I am a little confused... Are there SPOT colors in the artwork you are trying to hit on the iGen? If so, why not use the iGen's PMS matching. It gives you much more flexibility without mucking around with TRCs and all of the output intents. You should just be able to set 1 output intent, and adjust your PMS colors as needed. Just watch out- TRCs change your PMS colors for some stupid reason.

What is your front end for the iGen? I used a DocuSP front end and tried to match color on press. I found the best way was to embed every image in a PDF with our press profile and then use only 1 output intent. We just built a TRC to get it close and we were pretty accurate. Depending on the file, we had to modify the TRC occasionally, but I would say that 85% of the time we were close enough to the press to satisfy the customer.

[mbrennan5]

Im kind of confused what benefit profiling provides. I understand why I would want to profile to a different device, but what is accomplished when you create a profile and assign it to different stocks? My color analyst tried to explain it to me but I was too busy at the time to discuss.

[we3dumys]

Embedding profiles on all images I sent to the iGen helped with color consistency across the board. The other benefit was we had was the files we were feeding into the iGen were color managed as if they we were going to use them to generate proofs for press. This meant that our press profiles were used when the DocUSP converted to iGenCMYK for output- more accurate conversions. Feeding accurate/consistent files to your iGen (like everything else) makes it much easier to control and troubleshoot.

In your case though, since you don't have the profile (or the press to build a profile from), you are probably going to be stuck adjusting TRCs until you get the files right. You could try setting up a queue on iGen controller (Fiery/DocUSP etc.) with one set of settings, and just run EVERY job to that; at least you you would be doing the same thing every time. For anything too far out of whack, build a custom TRC...

[NigelT]

Hi There
It seems like you are trying to match a raw file from one color space to another. If your software cannot reRIP the data into the color space and print you have a problem.
As you know SWOP is Short Run Web Offset Press and Sheetfed has a different gamut.
Try using the ISO coated profile from FOGRA I know that the US has different tolerances but try it. Use this as your target in your IGen and I think you will like what you see.
I have used it on HP Indigo and it works great.

http://www.prepressforums.com/module...ted_v2_eci.icc

Regards
NigelT