press tests prior to profiling

[mlarmour]

What types of press tests would everyone recommend prior to profiling or before going down the G7 path to ensure the press is "in good shape"?

Thanks,

Matthew Larmour

 

[Lukas Engqvist]

Not done any G7, but generally before profiling:

Make sure your prepress workflow is flawless.
30% of each colour, full sheet tone to test for defects in blankets, uneven colouring etc.
concentric rings, to test that no movement, doubling of print
Linearisation on setter and in press. (documenting is key to repeatability)

 

[jardo]

I would run the GATF suite of tests. You can check their web site for the latest. It can be quite overwhelming to run all the tests, so I recommend getting professional consulting for the first time that you do it. Take good notes and you won't need them again. I know Ray Prince with NAPL does this type of service and he'll be brutally honest with the quality of your press. Good luck!

 

[Bret Hesler]

GATF has some nice mechanical test forms, and Idealliance is developing a G7 pre qualification test form. You can check it out on the g7global.org website. Basic elements you will want are ladder targets to check for movement, register targets, solid bars around the cylinder to measure density falloff.

The 30% tint test lukas mentioned is a good one. We added single color tints to see which units were problematic.

Bret

 

[RGPW17100]

I would recommend getting Fuji or Pitman to help. For 6 K a Fuji guy was with us for 3 days doing three profiles for our SM52 and for our Oris proofer. We did was download the idealiance target and ran them linear and kept our densities as close as we could then sent the trainer a copy so they could look at it to determine if there might be a mechanical problem with our press that would interfere with the qualification. The preliminary test they found no problems and then we scheduled them to come out.. After the three days we were able to do our own G7 profiling. You will need a plate reader, densitometer and a photo spectrometer and a bunch of stock. You will only be able to qualify coated stock. Uncoated stock will not produce a good enough color gamut to qualify.

 

[Cspearman]

uncoated paper press profile

uncoated paper press profile

I have an opportunity to profile a press that will be running uncoated paper for my catalog. My profiling chart has some squares that have a density of 400%...the suggested max density for imagery on this kind of paper is 260%

Usually charts should be printed as is...however, if left as is the squares (due to dot gain) may bleed out and ruin the other patches...and if converted to an uncoated profile, that
may yield it invalid.. Does anyone have any thoughts on this?

 

[meddington]

I have an opportunity to profile a press that will be running uncoated paper for my catalog. My profiling chart has some squares that have a density of 400%...the suggested max density for imagery on this kind of paper is 260%

Usually charts should be printed as is...however, if left as is the squares (due to dot gain) may bleed out and ruin the other patches...and if converted to an uncoated profile, that
may yield it invalid.. Does anyone have any thoughts on this?

If you have ProfileMaker you can design your own test target and limit the TAC to a lower amount. Published characterization data (Fogra29 for example) uses the same targets with no ink limiting however.

 

[Cspearman]

I have profilemaker but it doesnt give me a one page chart option...thats what I am limited to unfortunately.

 

[meddington]

What instrument are you using? You should be able to generate a new test chart for 1 page, though your patch count might be lower.

 

[Cspearman]

Eye one spectro (handheld) and an xrite Dtp41


Uhm...Ill look again but it seemed all the charts were multi paged. And I am trying to avoid the dtp41...its a pain to get working right.

 

[meddington]

In Test Chart Generator (within the MeasureTool Module), if you go to the "New Testchart" tab, you can select the number of pages. The number of patches generated would then be based on the patch size and sheet format for the specific instrument you select. This is of course a custom target, but with limiting the TAC, you'd be using a custom target anyway.

 

[Cspearman]

Tried it...it works, the problem is in getting it to fit one page uggg