G7 question???

[tomatron]

The curves that I created through Color Path Sync for our offset press matches our Indigo proof, but is a little on the washed out side compared to the indigo. I think its printing too sharp. How should I handle this? Should I evenly increase the dot at all curve points to increase the TVI? The TVI on average is about 1-2% higher on the Indigo than the 3 press.

Thanks in advance.

 

[Alith7]

wait. first you say it matches, but then you say it's washed out...

First thing to check is if your proof is passing spec.
If that is good, then you should confirm that all your Color Path settings are correct for the ink you are using. (you can get that information from your supplier)
If that passes, then check your color path information and see where you are at, make sure you are falling where you want it to be. Especially look at your dot gain curves and percentages.
Last resort (what we had to do, as color path was not 100% to where we needed to be) manually adjust your curves, but NOT blanket adjustments. Assess where you need to push the colors, and the adjustments should be in a smooth curve. with very small adjustments in the higher and lower percentages, and your largest moves in the 40-60% range. ****WARNING**** you should NOT do this unless you have a VERY good understanding of the color management process. If you do not, color path comes with tech support, contact support and ask them for assistance. That's why it costs so much!

 

[rich apollo]

You have to decide which is going to be your reference. Is your press printing too sharp, or is your Indigo printing too heavy.

You really have 3 choices:

1) SWAG - Scientific Wild A$$ Guess

2) Print another test target

3) Use a smaller colorbar type target to see which device is in spec, and which is not.

I don't know about ColorPath, but there are some other tools, like pressSIGN, that can give you the feedback you're looking for from a colorbar. The colorbar(s) can be included in regular jobs, so you can track performance and make adjustments.

 

[meddington]

If you're following the G7 methodology, measurement of the neutral print density curve should indicate if the devices are hitting tonality targets, and render necessary adjustments for the press.

 

[rich apollo]

Sounds like the original poster is trying to avoid another press run.

 

[meddington]

Sounds like the original poster is trying to avoid another press run.

I see. I would still utilize neutral print density measurement as the basis for curve adjustment, provided the highlight, midtone and shadow gray patches were present on the control bars. If not, we're back to SWAG.

 

[tomatron]

I'm using the Idealliance 54 patch control strip and both machines get a pass in Oris except for the Delta H on mag. for the press. Color wise they match very well its just the the indigo seems to have more weight to it. The NPD's are very good for both devices??? As suggested I will put a control strip on the press again to verify the NPD as I have been going by the data from the original confirmation run I created the curves from. Maybe something has changed on the press.

Thanks

 

[meddington]

Is the Indigo printing higher primary solid ink densities? The NPDC targets are dynamic based on the devices achievable solid density, so it is conceivable that two different devices could have different tonal results. If the Indigo was being color managed via ICC profiles, this should be less of an issue, but...

 

[rich apollo]

Is the Indigo printing higher primary solid ink densities? The NPDC targets are dynamic based on the devices achievable solid density, so it is conceivable that two different devices could have different tonal results. If the Indigo was being color managed via ICC profiles, this should be less of an issue, but...

That dude is wicked smart!

 

[meddington]

That dude is wicked smart!

thanks Rich...but your bar may be set a bit low.

 

[tomatron]

Ok, I verified the NPDC on the press and they are very good in Color Path Sync. I believe its the Indigo thats printing a little heavy. How often should the Indigo be re-profiled?

 

[Alith7]

Ok, I verified the NPDC on the press and they are very good in Color Path Sync. I believe its the Indigo thats printing a little heavy. How often should the Indigo be re-profiled?

The "experts" answer:
any time you change ANYTHING. Blankets, ink, water, packing, plates, humidity, turn left instead of right when you take the plates out of the burner....

the reality:
major seasonal shifts (dry winter - to - humid summer), when you change anything major (switch plate manufacturer, ink supplier, etc.), when you start seeing a major difference in your spot checks or you're having trouble matching your proofs.

In my shop, I generally would prefer to do a curve check/tweak every 3-4 months. though the reality is I get it about once every 6 months.

 

[meddington]

Ok, I verified the NPDC on the press and they are very good in Color Path Sync. I believe its the Indigo thats printing a little heavy. How often should the Indigo be re-profiled?

Re-profiled...probably not that frequently. Calibrated...frequently. I monitored an Indigo 5000 for three years and re-profiling wasn't necessary, so long as calibration and maintenance were on a regimented schedule. Your results may vary.

 

[Alith7]

Re-profiled...probably not that frequently. Calibrated...frequently. I monitored an Indigo 5000 for three years and re-profiling wasn't necessary, so long as calibration and maintenance were on a regimented schedule. Your results may vary.

I misread that. Yes, re-profiled, rarely. I was talking about calibrating.
-->although with ColorPath, you use pretty much the same process, it just shouldn't take as many press pulls.

 

[tomatron]

Our Indigo is a new 7600 which is supposed to do a calibration run automatically daily. When I look in Oris I notice that on all 54 patches the L* is about 2-3 points lower for the Indigo than the press. Wouldn't that be why the indigo seems to print with more weight?

 

[meddington]

Our Indigo is a new 7600 which is supposed to do a calibration run automatically daily. When I look in Oris I notice that on all 54 patches the L* is about 2-3 points lower for the Indigo than the press. Wouldn't that be why the indigo seems to print with more weight?

Can't speak for your device, but the 5000 did automatic color adjusts, but also benefitted from periodic Lut generation and validation, which would adjust the tone curves toward their original values. These were initiated manually by the press operator.

Lower L* = more weight. If your solid densities on your indigo are higher than that of your offset press, you may want to lower them to match, then perform G7. Or, you could potentially create a profile of your offset conditions and use that as the simulation profile on your indigo. I found closer visual matches by utilizing ICC profiles on the Indigo than trying to match via Solid primaries and tone curves.

 

[tomatron]

What would be considered acceptable in terms of how much the Indigo drifts from day to day? For e.g.. I'm seeing on the 50-40-40 patch a delta E of 2.09 one day and 4.29 the next day which is quite obvious to the eye. I know that the digital devices do drift, just not sure what is considered normal?

Thanks in for everyones input.

 

[meddington]

What would be considered acceptable in terms of how much the Indigo drifts from day to day? For e.g.. I'm seeing on the 50-40-40 patch a delta E of 2.09 one day and 4.29 the next day which is quite obvious to the eye. I know that the digital devices do drift, just not sure what is considered normal?

I always recommend sticking to the recommended maintenance and calibration schedule, as well as best process control practices, and measuring and tracking results over a period of time. From here you can see what is "normal" deviation and you can set targets and tolerances based on what your device/workflow is capable of achieving, rather than an arbitrary tolerance that you may or may not be able to hold to. Akin to a Six Sigma approach.

My personal experience with Indigo devices is that they are fairly consistence for a production device, but I was not truly comfortable using them as a proofing device, particularly in color critical scenario. Whether or not a drift from 2.09 to 4.29 for a 50, 40, 40 patch is indicative of a color issue is subjective. Its certainly indicative of device drift, but your color not be overtly effected depending on image content.

 

[rich apollo]

A friend of mine who has very long experience with the Indigo, monitors sheets as if running an offset press. They pull a sheet every 40 sheets, or so, and read a colorbar with a spectro. Yes, they make adjustments constantly.

Most folks don't watch these devices enough. If you don't keep an eye on them, they sneak out and vandalize mailboxes, and stuff.

 

[meddington]

Most folks don't watch these devices enough. If you don't keep an eye on them, they sneak out and vandalize mailboxes, and stuff.

Ours went Goth.