Search found 165 matches

by jrburns47
Sun Jan 23, 2022 12:44 am
Forum: AgX
Topic: Reuse of Pyrogallol developer
Replies: 46
Views: 60328

Re: Reuse of Pyrogallol developer

Dumb question, to which I believe I’ve known the answer for decades, but one needing an answer please. If I’m reading 25mw CW at the recording plate surface, with a Newport wand detector 818-ST with no attenuator, with a normally reliable Newport 840-C light meter, and I make a one second exposure, ...
by jrburns47
Tue Jan 18, 2022 6:21 pm
Forum: AgX
Topic: Reuse of Pyrogallol developer
Replies: 46
Views: 60328

Re: Reuse of Pyrogallol developer

Yes, read your interesting writeup on pgs 43-52 of your informative 58 page Darkroom writeup on your website. Thank you. There seem to be different opinions about the best solutions and methods. I wonder if anyone has had actual experience and success trying your approach or Jeff B’s approach on old...
by jrburns47
Sun Jan 16, 2022 12:57 pm
Forum: AgX
Topic: Reuse of Pyrogallol developer
Replies: 46
Views: 60328

Re: Reuse of Pyrogallol developer

It’s a mystery to me. Attaching a photo of the SP696T sensitivity curve.
by jrburns47
Sun Jan 16, 2022 11:31 am
Forum: AgX
Topic: Reuse of Pyrogallol developer
Replies: 46
Views: 60328

Re: Reuse of Pyrogallol developer

Thank you Dinesh. I’ve only got a few of the 10E75 plates but a lot of the old 10E75 film! Yes, please do forward the 1969 10E75 paper when you have a chance😊. For the most part, I never took 10E75 seriously - viewed it mainly as a teaching material. After my recent tests though, I have to change my...
by jrburns47
Sun Jan 16, 2022 10:20 am
Forum: AgX
Topic: Reuse of Pyrogallol developer
Replies: 46
Views: 60328

Re: Reuse of Pyrogallol developer

Hi Martin, Thank you for taking the time to reply. The “acutance dye” being an anti-halation dye? When I was using the 3-step alcohol dry process many years ago in which I observed a pink hue left in the 50/50 bath, it was mostly with Agfa 8E56HD and Millimask plates. I’m testing a possible new 660n...
by jrburns47
Sat Jan 15, 2022 10:56 am
Forum: AgX
Topic: Reuse of Pyrogallol developer
Replies: 46
Views: 60328

Re: Reuse of Pyrogallol developer

Hi Petr & Ed, I used to use the three step alcohol dry plus spray to dry my white light transmission holograms. A side benefit that I never thought much about was sensitizing dye removal although it was hard to miss the color change of the first alcohol 50/50 bath. Now I’m using Pyrochrome proce...
by jrburns47
Wed Jan 12, 2022 3:36 pm
Forum: General Holography
Topic: Bayfol HX polymer
Replies: 5
Views: 6079

Re: Bayfol HX polymer

Realistically, it won’t. Most still here using HX200 are doing commercial work, mostly HOEs, I suspect, and are, not unreasonably, concerned about “trade secrets” and some have NDAs about their projects. Others just aren’t naturally communicators or sharers - they ARE holographers afterall😂… Only a ...
by jrburns47
Wed Jan 12, 2022 12:02 pm
Forum: General Holography
Topic: Bayfol HX polymer
Replies: 5
Views: 6079

Re: Bayfol HX polymer

Why not write it up?
by jrburns47
Thu Jan 06, 2022 11:01 am
Forum: General Holography
Topic: Dielectric mirror mystery
Replies: 6
Views: 5238

Re: Dielectric mirror mystery

Thank you John & Dinesh & Joy for your thoughts on this odd observation. I’m NOT going to dwell on it now since I’m on a deadline testing the 660nm laser and it would be all too easy to get sidetracked trying to understand what’s actually going on🤪😂! Since I don’t currently have any mirrors ...
by jrburns47
Wed Jan 05, 2022 5:56 pm
Forum: General Holography
Topic: Dielectric mirror mystery
Replies: 6
Views: 5238

Dielectric mirror mystery

Hi all, I’m testing a 660nm laser. I have both aluminum and dielectric 1” steering mirrors. The dielectric mirrors were bought years ago & coatings were AR optimized for 514.5nm. The mystery is that the OB measured power is ~38mw. When I measure it again after reflecting of an aluminum mirror, i...