Discussion in '4-Color Offset Presses +' started by bennie, Nov 9, 2009.
Hope someone kan help I need density values on uncoated stock
I used to read the values of the CMYK in the uncoated section of the Pantone book
Std densities for coated ...
c 1.50 m 1.45 y 1.00 k 1.70
uncoated I don't have (they're not given in my copy of the PMS book... but my suggestion would be to achieve those densities on a coated stock then run your uncoated material straight after (in the same run) then take density readings.
Having said that, I reckon you're going to have to increase ink weights to achieve an acceptable result.
I WOULD START AROUND THE MARKS OF k= 1.30 c=1.05 m= 1.00, y=1.00, THEN SEE HOW IT LOOKS TO THE PROOF FROM THERE, i note most densos give different readings, even the same brandsometimes.
thanks for the advice all
I think I would start a Richards settings you will probably need to come up in weight about 18% on uncoated stocks.
Sorry, i'm with Lyle on this one except i may increase the black to 1.35 and decrease the yellow to 0.95.
Obviously, these figures will depend on stock and desired result but that is where i would start from.
I may be too late but I found my handy little card given to me by a salesman. c-1.00 m-0.95 y-0.80 k-1.25. Hope it helps.
Hi guys, Just wanted to chime in on the offset density values. We run pretty close to the ranges stated at our place. We run alot of offset with four color process. We feel that keeping the values down is a must, but you also need an ink that has good pigmentation or you run the risk of pushing to much ink to the plate with a weak ink. Very frustrating to have to wait on first pass to dry. Not to mention the risk of picking the first pass if the ink does not dry back hard enough. thanks..
I will advise you to make with your your ink supplier. They have often the "correct" recommended density values for that color you use. By using their values you will have a correct color balance "Grey tone" and you will also achive the best print result that colour can give +/- a little factor that is looked to quality of the press itself.
Normally when I have been running with Density's on uncoated it was around c-1.00 m-1.05 y-0.85 k-1.30, But it all depends on the proof(s) of what your trying to match. If you are eye balling it then these are good numbers to start at for rule of thumb. But remember it's always easier to put more ink on the sheet then it is to take it off. I would undershoot the numbers at first (depending on how much spoilage you are being allowed) and if your running books of waste ect.
Density values on uncoated paper
Or density values year 2010:
Uncoated paper:Y: 1,15
Density is not an answer with inks. I have seen a black read @ 1.25 and look black and I have seen another series of ink that 1.25 looks washed out. In my opinion you can have weight (density) and lack pigment. Are you printing linear or using a curve on your plates. You can print a 175 line screen on offset using a curve and you would be amazed at how brilliant the printing looks. Densities are just numbers and ink companies love to slack on pigment. What looks good is where it should run. Use the densitomiter for nothing but color consistency. If your shop has not fingerprinted your press on offset and unncoated than you'll are really missing out on the full potential of your printing. Last shop I was at I printed K- 1.45, C 1.25, M 1.25, and Y @ 1.00 on offset and opaque stocks. We could have never carried this kind of weight before using the 175 line screen before the curve but after perfecting the curve, WOW!!!!! It was almost like printing on coated as far as resolution and detail. It is the only way to go!
I agree Loupeyeyed - It's all too tempting to print by 'numbers'.
All the density targets in the world won't mean jack sh•t if the job doesn't look 'right'...and that isn't that the basic skill a Pressman should have?
guess iam 1 of the oldtimers here that can tell you that if you know your press,your inks and the very very important ink water balance.. LOOK at what you are printing, watch how much ink your ink ductor is taking from the ink ball,take control of the press look AT THE PRINTED SHEET AND YOU TELL THE MACHINE WHAT TO DO INSTEAD OF THE NUMBERS TELLING YOU WHAT TO DO.. when sheet looks good, appealing to you, close to color matching material,, then look at the numbers then enter them into your color console..
Exactly, Kbarz, I'm probably a youngster compared to allot of you guys on this forum but I've learned a lot in my small career. I've always had the mentality of figuring out why something is happening, whether it be wrong or right. A good set of eyes is better than any densitometer or other machine. I like to achieve gloss out of my inks when printing on coated stocks and on offset, print with good color strength and correct pressure. Always compensate for dryback, usually somewhere around ten points with the denso. That's just how I roll and it works for me.
thank you all for the advice this is what i like about the form
Great big thank you it is so easy to start doubting ones skills with all the technology
My feeling is that you should start from the press and work your way back. Run all 4 colors at levels that produce a consistent ink film thickness on the rollers. This ink film thickness should be even across the width of the press, and a thickness thats able to run stable, free from washing out, yet resistant to dry ups. It should be app. the same from unit to unit. It should be a thickness that has solid areas looking rich, yet not so dense that the sheet wants to set off. Once you've arrived at this stable ink film thickness then the printed sheet should be evaluated and any further corrections made in pre press. It should be noted that you can actually measure the ink film thickness with ,believe it or not an ink film thickness gauge. Some refer to this gauge as a Peto gauge. The temptation to make jobs happen on press should be avoided whenever possible. If colors are not matching then its time to get new plates with corrections from the pre press dept. If you strictly adhere to these suggestions you will find your presswork to be more consistent regarding color matching, color control throughout the run, and minimizing defects like dry ups, wash out, offsetting, etc.
If you do not have someone in your company thats capable of leading you through this very technical process of "fingerprinting" then I would suggest either hiring someone full time, or at the very least calling in a consultant fully familiar with the entire process.
I know this is probably old news,
I use vanson series 3 process inks.
My starting point for uncoated paper is
K >> 1.25
C >> .90
y >> .90
Pls. check ISO 12647-2 2013.
The basics of ink measuring is not density, but Lab!!!