Need Help about how paper effects color on press

[bgbs]

I would like to know how matte paper or glossy paper react to ink on press. Does matte absorb the color more into the paper thus making prints darker than glossy or is it the other way around?

Thanks

 

[gordo]

A rough, fibrous paper surface is composed of a multitude of non-uniform reflecting surfaces. When light strikes them, they scatter it randomly and, thus, adulterate the print with white light. The effect is a loss of contrast - blacks become dark gray. A color image can also tend to change its hue.
If tonal compensation has not been applied in the form of a plate curve or through separation techniques then there may also be a further loss in midtone and shadow detail and tonality.

best, gordon

my print blog here: Quality In Print

 

[Deleted member 16349]

I would like to know how matte paper or glossy paper react to ink on press. Does matte absorb the color more into the paper thus making prints darker than glossy or is it the other way around?

Thanks

In tests done with my Ink Transfer Blade technology which feeds a consistent amount of ink into the roller train, I was actually very surprised at how different the print density is when printing on coated paper when compared to printing on uncoated paper.

In the test, the same inks were used and the same plates and the only thing that was changed was the paper. Since the constant ink feed will result in the same amount of ink printed on the paper between both runs, it was very easy to see the difference in density. Printing the same amount of ink on coated paper resulted in a very much higher density value than when printing it on uncoated paper.

It suggests that printing of coated paper could save ink.

As Gordon described, it is a matter of how differently the light reflects off the two surfaces surfaces.

Of course print density is not colour but the same kind of surface properties that affected density will have an affect on colour too.

The tests actually printed this same image on coated, uncoated and plastic laminated substrate (different inks used for the plastic laminate) and was run to demonstrate how the ITB would print a consistent density that was independent of changes to water and press speeds. The only problem was with the plastic laminated substrate. When applying too much water, it affected the quality of print due to too much free water on the surface of the plastic. The ink was not washed out and was still on the surface but the excess water affected the quality of the printed ink. Of course this level of water was way out of the range one would normally run a press.

 

[Alois Senefelder]

The Influence of Paper on Color Printing

The Influence of Paper on Color Printing

Hi everyone,

Two Pdfs that are useful in explaining - the title of this "Thread"

Regards, Alois

 

[otherthoughts]

To add to the many helpful comments thus far. I would like to point out that the question,

"I would like to know how matte paper or glossy paper react to ink on press".

Can be a complex question depending on who you ask.

The reactions on press will change in accordance with each stock's unique characteristics. As pointed out by others, the superior surface efficiency and reflectivity on gloss coated stocks, typically result in a greater possible D-Max(density maximum), both for 4-color inks and spot-color inks when compared with what's commonly possible with matte coated stocks. Increasing the D-Max accompanies with it an increasing color gamut as well, provided the press is well run and maintained.

Another factor is the absorbency, or "hold-out" of the stock. For example, "cast coated" papers exhibit both high gloss and high absorbency characteristics. Whereas "super calendared", #1 premium gloss coated stocks exhibit high gloss but with much less absorbency(better hold-out) than cast coated stocks. More absorbent stocks "dry-back" more so than do less absorbent stocks, and therefore change the appearance of the sheet as it dries, more so than less absorbent stocks do. I do not mean to favor one coating over another, just to point out differences.

Another item to consider is that the higher the surface efficiency of a stock, the lower the amount of "squeeze" the pressman needs to apply to the stock in order to achieve uniform ink transfer to the stock. In other words, matte coated stocks typically require somewhat more squeeze than gloss coated stocks require due to their less uniform matte surface. More squeeze oftentimes results in more sheet fan-out, dot-gain and other negatives with respect to a job as was pointed out earlier.

Don't forget the "brightness" and "whiteness" of each stock, a cool-white gloss stock might show significant hue and gray balance shifts when compared to a warm-white matte coated stock.

The UCR/GCR settings might react with substantial differences on matte stocks when compared to gloss stocks and should be considered.

Lastly, there may also be noteworthy differences in the way varnishes and coatings adhere and behave between gloss coated and matte coated stocks.

As a general rule of thumb, gloss coated stocks will result in both higher quality results and less trouble on press, but not always. A great matte coated stock might trump a "dirty-low-down" gloss coated stock on a good day.

"Does matte absorb the color more into the paper thus making prints darker than glossy or is it the other way around?"

Typically gloss coated prints have a greater D-max and therefore can achieve darker shadows than matte coated prints. Absorbency has been discussed already as well.

I suspect that what you actually meant by "darker" was not D-Max, but rather the loss of dynamic range and all the accompanying detriments incurred alongside the diminution of surface efficiency from gloss stocks to unbleached newsprint. I think Gordo said it best,

If tonal compensation has not been applied in the form of a plate curve or through separation techniques then there may also be a further loss in midtone and shadow detail and tonality.

 

[bgbs]

Thanks for all your replies.
The reason why I asked this question is because a month ago I had an issue with my printer (sadly not local, and sadly no hard copy proofs are offered) when I ran a uncoated job type. It was my first uncoated job that I ran with this printer. I always print glossy with them and the results are desirably pretty good. When I used a color swatch book they hit the color and density on target. but this time on uncoated print the whole print came out at least, I'd say 20% darker, and less contrasty. Before sending it to print, as usual I printed a laser print for myself.

My question is, what should I do then when I send out a uncoated print job to the printer? How can I be sure to hit colors and density on uncoated paper close to what I get with glossy? I want to avoid future mistakes. Someone suggested to me something about checking dot grain in illustrator or photoshop, but I guess I dont know how that works.

Thanks -Ben

 

[No.12 Looks Just Like You]

color match coated v. uncoated paper

color match coated v. uncoated paper

The PMS books show the colors on both coated and uncoated stock; if you leaf through the books an compare the same PMS color, say 2995 blue for example, you'll see quite a remarkable difference in color, the variable being the paper surface. Could this be the problem, you looked at a coated swatch, and not an uncoated swatch? Often the color will be referred to as PMS 2995C or 2995U, to show it's meant to be the coated or uncoated surface.
Also, with respect to your printing out a laser for yourself, as a guide to how the printed job would/should look, that's a whole 'nother can of worms. You would have to calibrate the two, so they mimic the results of one another; they're two completely different methods of imaging, each with it's own characteristics that effect print quality. That's probably not practical, as you and the vendor would have to work together very closely indeed to achieve fidelity.

 

[gordo]

...because a month ago I had an issue with my printer (sadly not local, and sadly no hard copy proofs are offered) when I ran a uncoated job type. [SNIP]When I used a color swatch book they hit the color and density on target. but this time on uncoated print the whole print came out at least, I'd say 20% darker, and less contrasty. Before sending it to print, as usual I printed a laser print for myself.
My question is, what should I do then when I send out a uncoated print job to the printer? How can I be sure to hit colors and density on uncoated paper close to what I get with glossy?

The problem is one of setting/having correct expectations. That's a communication issue between you and your print supplier. The solution is in getting clearer communications. Your laser (or monitor) proof is not useful for color proofing if it does not simulate the presswork of your print service provider. If you are not receiving proofs from your supplier that reflect their presswork then you cannot know how the color will look. If you are receiving proofs from your print service provider that do not correctly reflect how their presswork will look, then you need to talk to them about the disconnect and how they are going to fix it.
You may be able to apply color management techniques to your laser printer so that it will better simulate the final presswork, however, if it is indeed possible, the process will likely involve some heavy lifting technically and certainly better communications than you suggest are happening now.
I think that you should talk to a local paper supplier (the ones that supply paper to print shops) they usually have educational books for designers that explain these issues. They will also have paper swatch books which show the same images reproduced on several different paper types. These samples can give you a "feel" for how color reacts on different papers.

best, gordo

my print blog here: Quality In Print