Dot gain

[LoganBlade]

ok  If I open a Photshop file and make a
25% SCREEN
50% SCREEN
75% SCREEN

and then open curves and bumped the 50% up to 70% imitating a 20% dot gain. Would the 25% and 75% reading be the gain the 2 measurements should be?

[Joe]

Tis my own opinion but I don't think so. I think if you have a 20% dot gain in the 50% patch then you'll have about a 25% gain in the 75% patch. Of course we mostly use Newsprint and I've found if something reads 75% in my file it will pretty much print as a solid on newsprint on our cold set press. On our heatset the gain is not as much. About 15% in the 50% patch and around 20% in our 75% patch. The type of paper, print process (press), and dot shape/screening type will all affect the dot gain too.

I know you can't always trust wikipedia but I found this interesting.

Dot Gain

[LoganBlade]

Tis my own opinion

Going with your opinion. I trust it. the 25 and 75 read about 14% so I think I am going with that.

[LRob]

I agree

[Ear]

Yep, dot gain isn't a flat 20% of the original value, it works on a curve and basically means that the dot is gaining 20% of it's own circumference with the 50% having the biggest outside circumference of any dots. It will taper off in both directions from the 50%. So the 50 may print 70 but the 75 should end up printing somewhere around 85%.

This is where stochastic is of great interest because it is an FM dot and all of the dots are the same size, they just vary in frequency. You still get gain but it eliminates the curve.

[LoganBlade]

thank you all.

[Joe]

Yep, dot gain isn't a flat 20% of the original value, it works on a curve and basically means that the dot is gaining 20% of it's own circumference with the 50% having the biggest outside circumference of any dots. It will taper off in both directions from the 50%. So the 50 may print 70 but the 75 should end up printing somewhere around 85%.

This is where stochastic is of great interest because it is an FM dot and all of the dots are the same size, they just vary in frequency. You still get gain but it eliminates the curve.

We get more gain in the 75% than we do the 50%. Probably from printing on recycled newsprint though. It's like printing on a sponge.

[LoganBlade]

I think that is why i need to know if my logic was good. I want the press to print 20% gain on the 50% K and if I do that i should be getting 14% on the 25% and 75%. I have a hope it will look great when I get it done. I want this for coated and uncated stocks. I use the same stocks 90% of the time so i can make 2 que s per press.

again thanks