It's kind of hard to find how to publish a blog; try looking for blog2print. I had a book made of all the previous pages in this blog. Considering the effort involved in doing it myself it is well worth the price.
This posting is the introduction to the second part of my work. Now I am able to coat large plates. Before, I was learning how to do that with small plates. Yesterday I photographed with the Korona View 8x10 camera and developed the plate. Here is what I got.
My main objective was to get a plate exposed and processed that I had coated. The other objective was to develop it in the center of the time scale so I could pin down the ISO.
A bracketed test plate 4x5 had been made; five exposures of one half second each were made; all of them showed image, and I chose 2 seconds for the 320 foot candles earlier in the day when the sun was on the side of the houses. It moved while I got the big K ready; that is a story in itself. The sun went behind some clouds so the foot candles dropped to 160. I used 4 seconds at f 6.3 or 2 1/4 ISO according to the test. Development for the test was in Dektol 1:3 for 2 min. 22 sec.. That is a lot. It was a thinly applied coat and went dark immediately. The Dektol package says 3-4 min starting at 3/4 sec.. If you make a scale of numbers every quarter second there are 14 in all and 7 to the center.
3/4, 1, 1 1/4, 1 1/2, 1 3/4, 2, 2 1/4, 2 1/2, 2 3/4, 3, 3 1/4, 3 1/2, 3 3/4, 4
Two min and 22 or 23 seconds was the center. If only three min. would be used as the maximum time in developer then less than two minuets would center. I think fog may increase with development but I used the longer scale anyway. I wanted to see how it would effect very light exposures.
The image was grossly overexposed. ISO may be 6 not 2 1/4 when developed to the center or 2 min.. I stopped development at 2 min..
If I had developed by inspection instead of time I'd have pulled the plate out in 30 seconds while there were still lots of lights showing in it. However, now I have a benchmark to gauge further work.
A Dark plate means less light is needed, If one processed to the center of the development scale.
The emulsion used was Formazo which is not made anymore at least as far as I know. It was applied thinly with an emulsion well.
Later on I'll try to make better photographs. This is incredibly dirty as well. I don't mind. Bigger contact prints won't show what a computer can see.
new note: the longer time of 4 min in developing is used in developing fiber based paper. 3 min is quite enough to do plates. 1 min is recommended for RC paper and 2 for Fiber based paper. One minuet is about right to develop plates with. I may have been developing too long.