Re: continued solarplate notes
\Christina Z. Anderson wrote:
2. Exposing is done in 3 stages--main exposure first for **15** minutes with the light source at 1/2 the distance of the aquatint exposure. Aquatint exposure SECOND--**15** minutes with the distance of the light 1 1/2 the diagonal of the vacuum frame measure. Post exposure 5 minutes. (on a Stouffers dark steps 8, 9, and 10 should be "clearly defined").
Maybe he's using a maglight to make his exposures. ;-)
With the inverse square law of light 1/2 the distance of the positive means it is 4x the length of exposure, correct? So Ponsaing's ratio of exposure is 4pos/1aquatint. Can you believe the length of his times??!! I can't read the text to see what his light source is, though, unfortunately. I can glean that he is using Japanese plates KM73.So based on your theory Chris, if my ratio is 1:1 screen/image, I could do 10 seconds/ 10 seconds, or 1min/1min, or 15min/15min and it wouldn't make a huge difference? This might be true to some degree if one is using imagesetter film for both, since the density of imagesetter film is so heavy. I'd expect the dots would change size as time is increased though, since the longer exposures would allow more light to sneak underneath the edges of the dots. Easy enough to test
Thanks for the posting!