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Interesting! Thanks for running this experiment! What film did you use? And did you use a glass plate on the bottom of the tray? When I do this, the film sticks to the glass plate and I think the developer wears out except near the edges where it is replenished as a result of agitation.Quote:
Originally Posted by Jim Noel
Agitation is performed by lifting 3 sides of the tray for each cycle.Quote:
Originally Posted by salvatore
My times will probably not suit you as my negatives are designed to make salt prints. 4-5 minutes at 75 deg.F gives the the DR I need. If I was going to print on silver gelatin paper or cyanptype or lakitype i would dilute even further.
I see no need for holders, or glass in the bottom of the tray. Careful handling at all stages eliminates scratches. When I learned to develop film in the 1930's all films had very soft emulsions so proper handling was a must.
If you use the plastic developing trays made these days they have grooves in them, the developer tends to flow faster down these grooves when agitation is initiated, causing uneven development. Also the trays have bumps in them from the moulds, so a protective sheet has been necessary to stop scratching of xray film. I put a sheet of cleaned xray film down over the imperfections and only occasionally find scratches.
Yeah, I think it depends on the tray you use. Mine have little bumps which are remnants of the injection molding process. There's one right in the middle of each of my flat-bottomed trays and it scratches the emulsion badly if I don't put glass over it. My agitation scheme is similar to Jim's and I use double sided film. With film such as ektascan br/a flipping the film shouldn't be necessary.
the best trays I have used are the plastic food storage trays you can buy at the dollar store, they are about 5 dollars a piece, when I shoot single emulsion x ray film I just use the btzs tubes.
Developing with the trays is something I particularly enjoy. Its quite therapeutic, gently rocking the tray waiting for that image to appear and then deciding in the faint red glow if its time to halt development or wait just a little bit longer to find that little bit more detail. When I flip the green film it always seems to have a lot more on one side than the other, on the half speed blue both sides seem to have the same amount of detail.
So, I got my first flash ever this week. It’s a studio flash that can put out f32 at 1 meter with a softbox attached.
I wanted to try it out and was pretty puzzled that my Sekonic readings for the relative power of the flash and my big continuous fluorescent lightbox did not seem to match at all.
Of course I did the tests with cheap Fuji x-ray film to start with and where I had equal power from two sides the flash side just didn’t register. It seemed to be something like 1.5 stops under.
So today, I did a 2x2 test matrix with Foma 100 and Fuji HR-E 30 with equal power and then 3:1 power according to my light meter. I rated the Fuji at EI 25 from my earlier stuff.
http://i.imgur.com/HzdU6gD.png
What was completely new to me that apparently there is reciprocity failure also at extremely short exposures? The flash barely shows on the x-ray film. Is this an effect of my rating it at EI 25? Is is off perhaps?
What is the color temp of the new strobe? Perhaps it's too warm for the x-ray film.
No, I think it’s pretty cold. 5600K. My tubes are also 5500K.
My rotary cutter makes a very clean cut on film/paper. Meopta brand -common in Europe, probably unknown in the US.Quote:
Originally Posted by salvatore
Much cheaper than the Rototrim,but similar design.
The difference,at least with my design,is that the cutting head compresses the leading edge just before the wheel cuts.
On a guillotine, the cutting action on the blade tends to skew the medium. For heavy card to thin paper,works fine.
For films-rotary almost essential imho.