Hi,
I am trying to make a H2 Copy from an transmission master. The master is about 30x40cm. I use a 25mW HeNe and PFG01. The Copy should be of 20x25cm. I can do a copy which is correct in geometry and all part of the image are visible. But I have issues with brightness. Can anyone explain his method to achieve bright white light reflection copies. Once I did a really bright copy years ago, but I can't remember were was the trick.
I mean,
* what Ratio do you use, and how do you measure it?
* How long do you expose?
* what's the best height of the illuminated master? I mean, I read that blocking light from the master to get a smaller slit results in a brighter copy. To which size do I block? 20x40? 10x40? 5*40?
Any other hints?
thanks a lot.
H2 Copy
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JohnFP
H2 Copy
As a rule of thumb and starting point for H2 copies, I always start with a ratio of 1:1 reference to brightest part of the object. In other words, block the reference beam and measure the "hottest" part of the object beam. Then adjust so that hottest part is the same intensity as the reference beam.
Do strip tests with the energy level that Slavich recommends for that plate as the central strip. A couple of exposures with less time and a couple with more time all on the same plate. You will have to block both sides of the plate for an H2 reflection do get the exposure test strips.
Do strip tests with the energy level that Slavich recommends for that plate as the central strip. A couple of exposures with less time and a couple with more time all on the same plate. You will have to block both sides of the plate for an H2 reflection do get the exposure test strips.