Remote Press Checks

[meddington]

The scanned image of the press sheet was then made available to a remote customer to "inspect the press sheet for registration, dot structure and traps, specify last-minute changes and confidently approve the job." No mention of color.

This PDF (circa 2003) does indeed mention color, comparing the scanned press sheet color to the digital proof. But again, can't find anything current on this product.

http://www.silberware.com/portfolio/writing_samples2/remote_director_brochure_i.pdf

 

[gordo]

This PDF (circa 2003) does indeed mention color, comparing the scanned press sheet color to the digital proof. But again, can't find anything current on this product.

Yup, there they do. But I guess it didn't work. Or there was no customer demand (which I doubt).

best, gordon p

 

[markf]

PressSign

PressSign

PressSign from Bodoni will allow the client to remotely check the press in real time for ISO compliance via the web..

 

[meddington]

PressSign from Bodoni will allow the client to remotely check the press in real time for ISO compliance via the web..

Solutions like these are great and I fully support their use. However, anyone ever have to deviate from the numbers to achieve a better visual match?
*Mike raises arm

 

[Flexo Grunt]

my previous employer.....a large multi location printing corporation, would take a digital picture of proof and print sample side by side and emailed the photo across country for approval.. caused more then a few chuckles at press and in prepress, but it worked for the customer......of course we had quite a few rejections later due to color being off....

 

[gordo]

However, anyone ever have to deviate from the numbers to achieve a better visual match?
*Mike raises arm

This true and very important. Also, due to how an offset press lays down color - what is happening in the color bar does not necessarily reflect what is happening in the live image area. Your color bar may be in spec but your live image color may be out.

my previous employer.....a large multi location printing corporation, would take a digital picture of proof and print sample side by side and emailed the photo across country for approval.. caused more then a few chuckles at press and in prepress, but it worked for the customer......of course we had quite a few rejections later due to color being off....

Your previous employer had the right idea. If you use a high speed scanner to scan the proof and then scan the live presswork you can make a comparison between those two samples. You don't need the scan to be color accurate to make the comparison. You just need the scans to have been done exactly the same way.

It's like using a ruler to measure two objects. If you are trying to confirm that the two objects are identical - it doesn't matter if your ruler is incorrect. For example, 12" ruler that is actually 12.5" in length will still allow you to determine if the two objects are the same length or not. That is the same goal with a press to proof match. You just want to know if the proof and presswork are the same.

For example does the color of the press sheet on the right match the target proof on the left in this image?

According to PhotoShop the color is different in the areas highlighted below:

So, even though the color of your displays may be wrong you can still determine if the press sheet matches the proof.

This was the principle behind the system that I referred to in an earlier post here: http://printplanet.com/forums/color-management/24336-remote-press-checks/3#post152915

best, gordon p

 

[meddington]

Your previous employer had the right idea. If you use a high speed scanner to scan the proof and then scan the live presswork you can make a comparison between those two samples. You don't need the scan to be color accurate to make the comparison. You just need the scans to have been done exactly the same way.

Of course there's the possibility of scanner/camera metamerism...where the capture device interprets the spectrally disimilar proof and press sheet differently than our eye interprets it under a given light source.

 

[gordo]

Of course there's the possibility of scanner/camera metamerism...where the capture device interprets the spectrally disimilar proof and press sheet differently than our eye interprets it under a given light source.

Yup that's a possibility. But the same problem would exist with a spectrophotometer if you were using it to measure proof and press sheet to confirm alignment.

Defining what is a match is not just a mechanical issue of measurement but also one of workflow that has to be worked out by service provider and customer.

best, gordon p

 

[meddington]

I didnt mean to discredit the idea, but nothings perfect and it's a real challenge to substitute technology for human perception. And eyeballs aren't perfect either. At least with a spectrophotometer, you would have the ability to determine the metamerism index, though of course with the limitations and potential disconnect with the live image area.

You might be interested in this one Gordo. There was a product I saw down at Clemson that was right up this alley. Pretty impressive.

NCIS 600 - MeasureColor.com - The Color and Appearance Measurement Experts - Color Measurement - Color Management

 

[glenncolorguy]

Remote Press Checks

Indeed, ICS did pioneer this idea several years ago, but the idea of a subjective eyeball-based remote press OK is still fairly exotic and subject to some pretty rigorous requirements on both sides.

For most printing requirements, a more accessible approach is for the print buyer to specify colorimetric tolerance to a standard or specification such as GRACoL or ISO 12647. Adherence to standard metrics of solids and overprints, TVI and NPDC and gray balance usually will track quite closely with accuracy of visual match to proof, and in the cases where this would not be enough, a remote viewing situation would probably not suffice either.

Printing to standards with verification available to the print buyer is currently the best alternative to on-site press OK's.

 

[Chief_1975]

IFor most printing requirements, a more accessible approach is for the print buyer to specify colorimetric tolerance to a standard or specification such as GRACoL or ISO 12647. .

How do you decided what a fair colourmeteric tolerance is ?, printers will always want more latitude while printer buyers will want it as tight as a nuns thingy ma jig!

 

[glenncolorguy]

Tolerance

Tolerance

Right,there are "official" tolerances but in the end it is really an individual issue. Probably the best approach is for printer and buyer to agree on reasonable tolerances beforehand.