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screen printing => 4 Color and Simulated Process Printing => Topic started by: Artelf2xs on May 23, 2011, 03:42:57 PM
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As always for fun & entertainment as well as education! :o
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Dot gain should be controlled by the rip.
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Yorkie,
Some of do not use rip. We adjust manually to COMPENSATE for dot gain not control it. I am taling about the physical aspect that happen on press.
Dot gain happens.. in all forms of reproduction. some more then others.
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On press. I vote for 1-4.
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I'm thinking 1 though 5 myself. Anyone of them done wrong will have an effect.
Steve
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I'm thinking 1 though 5 myself. Anyone of them done wrong will have an effect.
Steve
I as well. I was looking for an "all of the above" option.
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Ok, so let's say out of all the options witch one will control dot gain the most? and I forgot to put... Sharpen your squeegee! :-[
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Dot gain is not a problem. We can handle it with several of the means mentioned. Variable dot gain (or any other variable) is a problem because if you are not sure what's going to come out, how can you compensate for it.
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If I had to pick one, durometer seems to be big in mind, triple durometer, 70/90/70, but really, all of them. Also, the wet white method, the one I learned was making a white printer that was the negative of the other 4 combined. We'd tape the 4 films together, cut a ruby mask around the outside, then create a negative from that stack, of all the white space between the dots of the 4 films. It worked pretty well, especially with the lower tensions of the day...
Steve
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you folks crack me up. Now an admin has added all the above.... My point is that one of the original mentioned is the most critical in controlling dot gain on press.
Not how to adjust films or screens for, or if it is a problem, or workaround solutions.
Which "ONE" element has the "MOST" impact on dot gain?
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Which "ONE" element has the "MOST" impact on dot gain?
The film!
Press gain is predictable and should be controlled upstream.
Anyone tweaking more than 2 of the variables listed has a completely out of control system. How far off must things be that you need to change the Squeegee angle AND Squeegee speed AND squeegee pressure AND Squeegee durometer AND off contact of screen to substrate AND Sharpen your squeegee??? SERIOUSLY, ALL OF THE ABOVE???
How long is the makeready, when everything needs to be tweaked? At the end of every job, are all of the settings restored back to normal or do you just start cranking knobs when the next job is way out of speck, because on the last jobs all of the settings were shifted?
Yes, the press does allow color to be tweaked on press, but the image should at least be in the ballpark when the press is started using the default values, but every knob turned and test print produced is money out the window.
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you folks crack me up. Now an admin has added all the above.... My point is that one of the original mentioned is the most critical in controlling dot gain on press.
Not how to adjust films or screens for, or if it is a problem, or workaround solutions.
Which "ONE" element has the "MOST" impact on dot gain?
Now that you've clarified it some more, I still think durometer (sharpness included) over the others, but now that everyone wants to change the rules in the middle of the game, it's a little muddy. But with the screens already made, and maybe an older press that doesn't give you the speed and pressure controls (like an old Preceision Oval) the blade is it. Which one do you have in mind, Dave? Or do you want the discussion to go a bit further before you reveal your answer?
Steve
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So do you have a stock of dull squeegees for when the ink is printing too heavy or do you dull them when using sandpaper (?) when you need a dull squeegee?
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Press gain is predictable and should be controlled upstream.
Again, Dot gain does not happen upstream ! It happens as ink gathers around the edge of the stencil ON PRESS!
Predictable yes.
Simple question. One answer!!!!!! Multiple choice! not Rocket science,,,, sheeesh,.
Which One single answer has the MOST effect of dot gain ON PRESS!!????
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Simple question. One answer!!!!!! Multiple choice! not Rocket science,,,, sheeesh,.
"In the RIP only" was added as one of the multiple choices!!!
OK, so the color on press doesn't match expectations, something has gone wrong.
The first questions is if the issue is with one screen or all of them??
Then the question is if the screen looks correct or not. If the screen is correct, there could be a problem with the squeegee setting or it could be an ink issue or a shirt issue.
I don't look at a dull squeegee as tuning point, as much as it is a maintenance issue.
But if i had to pick one, not including pressure or speed, i'd pick squeegee angle.
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so the color on press doesn't match expectations,
It is not about expectations or compensations. It is a simple question about the physical mechanics.
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To me off contact should be the biggest culprit out of the list,other than no. 7 , if your off contact is to high for whatever reason the stencil on the shirt side will enlarge has you force it down. take a peice of sheetmetal drill a hole in it and then bend it around an arbor the outside will grow. The same will happen to your stencil.
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To me off contact should be the biggest culprit out of the list,other than no. 7 , if your off contact is to high for whatever reason the stencil on the shirt side will enlarge has you force it down. take a peice of sheetmetal drill a hole in it and then bend it around an arbor the outside will grow. The same will happen to your stencil.
A lot of people probably forget about this one.
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So, do we have a consensus yet?
Steve
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so with a screen on the press and needing less or more ink . . . I find most of the above will give you a range of adjustment.
But the widest range, in my experience, comes with the squeegee duro. Most others will give me about 30% plus minus (that's in usable range, if you back the pressure off so much that you are not really printing or is not clearing enough it really is not usable). Going from a solid 80 duro to a triple 55 I see an increase of approximately 50%. That would make it the widest range once the screen is on the press.
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But the widest range, in my experience, comes with the squeegee duro. Most others will give me about 30% plus minus (that's in usable range, if you back the pressure off so much that you are not really printing or is not clearing enough it really is not usable). Going from a solid 80 duro to a triple 55 I see an increase of approximately 50%. That would make it the widest range once the screen is on the press.
30% and 50% adjustments, sound like too large of a jump to be considered a "tuning point" for dot gain.
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But the widest range, in my experience, comes with the squeegee duro. Most others will give me about 30% plus minus (that's in usable range, if you back the pressure off so much that you are not really printing or is not clearing enough it really is not usable). Going from a solid 80 duro to a triple 55 I see an increase of approximately 50%. That would make it the widest range once the screen is on the press.
30% and 50% adjustments, sound like too large of a jump to be considered a "tuning point" for dot gain.
In our case I have 6 different duros, so there is quite a range.Yes, you are right, It is not a seamless adjustment, but this is complemented by the other factors. Does that make the other factor more important? hmmm . . . .
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If you were a DJ at a nightclub and were switching from one song to another, you'd expect the volume settings for the second song will be correct. Then when you cut in talk on the mic, you expect the sound levels will be correct. Then if you switched an MP3 player, again you'd expect the sound levels to be correct. This is because before the show, you did a sound check. You know the volumes will be correct, because you have tested it. Now this is not to say, that from the first fan to enter to room, till hundreds of people enter the room, that you will not have to re-adjust the sound level. These are controlled require gentle adjustments, not the swapping out of amps halfway into the show.
Now imagine a show starting up, then realizing that amps are too small, shutting down the show, swapping out amps, doing a new sound check, then realizing these were still the wrong amps and swapping them again. Is this REALLY the way to put on a show?
The setting on the soundboard depend on the amp which is chosen, not the other way around. The choice of the squeegee should be made when planning the show. On the day of the show, you may need to panic and swap equipment, but it should be the exception, not the rule.
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If you were a DJ at a nightclub and were switching from one song to another, you'd expect the volume settings for the second song will be correct. Then when you cut in talk on the mic, you expect the sound levels will be correct. Then if you switched an MP3 player, again you'd expect the sound levels to be correct. This is because before the show, you did a sound check. You know the volumes will be correct, because you have tested it. Now this is not to say, that from the first fan to enter to room, till hundreds of people enter the room, that you will not have to re-adjust the sound level. These are controlled require gentle adjustments, not the swapping out of amps halfway into the show.
Now imagine a show starting up, then realizing that amps are too small, shutting down the show, swapping out amps, doing a new sound check, then realizing these were still the wrong amps and swapping them again. Is this REALLY the way to put on a show?
The setting on the soundboard depend on the amp which is chosen, not the other way around. The choice of the squeegee should be made when planning the show. On the day of the show, you may need to panic and swap equipment, but it should be the exception, not the rule.
I agree, and the reality is that the angle (primarily) and pressure (secondary) are used first. So in the spirit of the poll, they would be better.
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BuwA HAHAHAHA ::)
if you where riding a horse in the desert, Because you left you camel in an unlocked house in Canada, ( But at least the coffe pot was off) And you remembered that the art of screen printing, invented over 4000 years ago had advanced a lot. But yet the same simple rules applied.
would you still sweat?
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I agree, and the reality is that the angle (primarily) and pressure (secondary) are used first. So in the spirit of the poll, they would be better.
It would be best to get it down to angle OR pressure.
"control" is all about control. When a process is under control, the screens made on monday can be remade on friday or remade next year and the results will look consistent. The printing of a screen made today, should print the same with one made next year.
The payoff of control is rapid quicker make ready. Fiddling with angle and pressure before deciding to swap squeegees and start adjusting again take time. The higher end the product, the tighter the color requirements. I've seen makeready disasters, when multiple remakes eats hour after hour.
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Sorry yorkie and others,
I guess I could have been clearer about this being rudimentary knowledge.
Not about computers ( Which are not needed to screen print) or rip software ( which is not needed even with a computer) or sound boards ::)
it is about screen printing... Pulling a squeegee over a stencil supported by a mesh fabric.
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Sorry yorkie and others,
I guess I could have been clearer about this being rudimentary knowledge.
Not about computers ( Which are not needed to screen print) or rip software ( which is not needed even with a computer) or sound boards ::)
it is about screen printing... Pulling a squeegee over a stencil supported by a mesh fabric.
well, we seem to have an abundance of opinions here, are you sure your answer is going to satisfy everybody?
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Before computers, dot gain was controlled with exposure calculators and duplication of film or in the creation of the art.
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BuwA HAHAHAHA ::)
if you where riding a horse in the desert, Because you left you camel in an unlocked house in Canada, ( But at least the coffe pot was off) And you remembered that the art of screen printing, invented over 4000 years ago had advanced a lot. But yet the same simple rules applied.
would you still sweat?
Is it daytime or night time? (And yes, the falling tree does make a sound even if no one is there to hear it))
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Before computers, dot gain was controlled with exposure calculators and duplication of film or in the creation of the art.
you still don't get it.. dot gain was compensated for with the exposures... you canot control dot gain on the film as it does not take place there!
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Press gain is NEVER controlled on press!
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Press gain is NEVER controlled on press!
::)
All-righty then... Thanks for playing.
But SERIOUSLY :o ::) Serious?
That's got to be up there with one of the most obtuse statements I think I've ever head somebody make.
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;D