Colour standards and correction for offset

mulo_g

Well-known member
I am in postpress industry. I accept printing jobs and outsource to offset printers. Artwork is supplied by clients. I am many times overwhelmed by rejections, mostly due to colours unacceptable by clients. I suspect clients supplying files unsuitable for offset. Sometimes I am unable to do good lamination due to heavy ink patches. Sometimes heavy patches hiding the images.
Are there any colour standards universally or mostly acceptable? I have come across words like fogra, Swop. How do I check suitability of files? Any software for checking and/or correction?
 

Puch

Well-known member
Enfocus BoardingPass might be a help for you. If you need more, you have to dig down deeper and understand printing basics like overprint, knockout, total ink coverage, spot colors, printing standards. There is a ton of resources out on the net to learn from. After that, you have to get a professional-level inspection/repair software to correct customer files, so Acrobat Pro or Callas pdfToolbox is a must.
 

abc

Well-known member
I think you might be using the 'wrong' offset printers!!
The right ones would have approached you to iron out these problems before they went to press!
 

namelessentity

Well-known member
You may also need to find better vendors. We've had a few trade vendors that just don't appear to have any quality standards, and you could give them perfect files and never get a good product in return.
 

Ulrich

Well-known member
might be on this site, you will find any more helpful downloads or just informations:



As said already before this is to all the brilliant folks here on this planet, they are always ranting against all the different standard organizations in our business´s world, because these organizations are sending and not paying bills, too ;-):

You need ideally vendors they are able to serve the neccessary standards (or minimum to understand what is claimed by them...), they are empirically and sience based examinated (and claimed) by that organizations!

That standards are a great help, but not a guarantee in every case (there are regulated tolerances in there...)

By problems with color the minimum basics you (or your clients making the files) should know/must study are:


different gamuts in different and in the same color modes
(see also: Rendering Intents...
...and just one more example: what could a different mode - subtractive or additive - mean for the same transparency effects either in rgb or cmyk...)

OutputIntents (which icc profile is for which intent/special technic and special substrates)

what happens normally to a primary and secondary color separation by converting in the same mode from CMYK coated to uncoated)

"overprint" and "knockout" in a separation

TAC (Total Area Coverage) and how to change it ...

which SpotColor is out of CMYk-Gamut...

not wrong for understanding Offset is to know a bit of TVI (Tone Value Increase), too


But first of all you should perform a for both sides helpfull communication-culture with your customers to see how expactations would match or fail the technically chances...
 
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mulo_g

Well-known member
Enfocus BoardingPass might be a help for you. If you need more, you have to dig down deeper and understand printing basics like overprint, knockout, total ink coverage, spot colors, printing standards. There is a ton of resources out on the net to learn from. After that, you have to get a professional-level inspection/repair software to correct customer files, so Acrobat Pro or Callas pdfToolbox is a must.
At the age of 63 I still feel it's never too late to learn. Are there any books on current practices in offset printing and colour? Any specific website?
 

Ulrich

Well-known member
At the age of 63 I still feel it's never too late to learn. Are there any books on current practices in offset printing and colour? Any specific website?

this is okay and for free, but unfortunately first you have to learn german language ;-) :



this is in englisch, also for free, but more for already educated people, i do not find yet, but remember some very few "mistakes" in there :



there must be a also free brochure in english from heidelberger "colour-and-quality",
but sorry i do not find it yet, might be someone share an actual download link for the english version here...?
(in german: https://www.hpv-ev.org/upload/fachwissen_farbe_qualitaet.pdf)
 

SteveSuffRIT

Well-known member
If outsourcing printing, you can ask printer to provide data or samples from their production run.
It's called a Certificate of Compliance or Analysis (COC, COA)
Then I would verify with my own sampling from what they send you.
Why get a customer complaint or rejection after all the extra finishing-bindery work you put into a job.
Know the status of the their printing before you start any work.
 

marktonk

Well-known member
Hi Ulrich,

Here is a link where you can get the English version of "Color and Quality".


Best,

Mark Tonkovich
HeidelbergUSA
this is okay and for free, but unfortunately first you have to learn german language ;-) :



this is in englisch, also for free, but more for already educated people, i do not find yet, but remember some very few "mistakes" in there :



there must be a also free brochure in english from heidelberger "colour-and-quality",
but sorry i do not find it yet, might be someone share an actual download link for the english version here...?
(in german: https://www.hpv-ev.org/upload/fachwissen_farbe_qualitaet.pdf)
 

danremaley

Well-known member
I am in postpress industry. I accept printing jobs and outsource to offset printers. Artwork is supplied by clients. I am many times overwhelmed by rejections, mostly due to colours unacceptable by clients. I suspect clients supplying files unsuitable for offset. Sometimes I am unable to do good lamination due to heavy ink patches. Sometimes heavy patches hiding the images.
Are there any colour standards universally or mostly acceptable? I have come across words like fogra, Swop. How do I check suitability of files? Any software for checking and/or correction?
Email me and I’ll send you a copy of the best book I know for color reproduction.
‘Color Control in Lithography’
danremaley@comcast.net
 

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