Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison
that is the last thing i want to run into is over exposing. Thanks a lot for the good info! it surely has help me out a lot and decide better on what i will be using!
that is the last thing i want to run into is over exposing.
I'm posting from a phone, which I don't type well on, but here's a good overview:[url]http://m.youtube.com/watch?v=QUNjF7XB7AM/[url]Basically, I found the exposure speed of photopolymers (PP as they are sometimes called) to be problematic when exposed with these new LED units. Its very easy to overexpose, and most using PP & LED exposure are using different exposure times for each different mesh counts. For me, its easier to have a slightly longer exposure time and keep it the same across all mesh counts. Plus, we do some waterbase, discharge, and even solvent/air-dry printing, which PP emulsions will not hold up to.
I think the point is at 4 seconds there is less latitude for error vs 45 seconds. If you go half a second longer at 4 seconds then you exposed it 12.5% too long where as with 45 seconds 12.5% is over 5 and a half seconds.
Quote from: Gilligan on November 30, 2014, 11:20:05 AMI think the point is at 4 seconds there is less latitude for error vs 45 seconds. If you go half a second longer at 4 seconds then you exposed it 12.5% too long where as with 45 seconds 12.5% is over 5 and a half seconds. That may be true but the real benefit of LED exposure is once you dial in your exposure time for proper cure it will never change unlike other types of units. To each his own but if I was just starting out I would definitely go LED.
Quote from: 244 on November 30, 2014, 12:35:51 PMQuote from: Gilligan on November 30, 2014, 11:20:05 AMI think the point is at 4 seconds there is less latitude for error vs 45 seconds. If you go half a second longer at 4 seconds then you exposed it 12.5% too long where as with 45 seconds 12.5% is over 5 and a half seconds. That may be true but the real benefit of LED exposure is once you dial in your exposure time for proper cure it will never change unlike other types of units. To each his own but if I was just starting out I would definitely go LED.With the less leeway granted by LED's shorter exposure times, calculating correct times for all various combinations is of even greater importance than before.I, and I suspect a lot of forum veterans, sincerely hope that a word to the wise is sufficient, and a new generation of screen makers will not necessitate frequent visits here by Step Wege Man (and of course, Exposure Lad)
Basically, I found the exposure speed of photopolymers (PP as they are sometimes called) to be problematic when exposed with these new LED units. Its very easy to overexpose, and most using PP & LED exposure are using different exposure times for each different mesh counts. For me, its easier to have a slightly longer exposure time and keep it the same across all mesh counts. Plus, we do some waterbase, discharge, and even solvent/air-dry printing, which PP emulsions will not hold up to for different reasons.