“Thin” Daguerreotypes

[Krokodul]

Dear all,

I have been making Daguerreotypes for two months now and have reached a bit of a problem. Compared to 19th century Daguerreotypes, my images seem to be really faint and are lacking contrast. The first two plates were fumed over iodine only (I takes two minutes to get to second-cycle yellow) and developed for 3 minutes at 90°C. I tried to increase the time over the mercury to 4.5 and 6 minutes. This resulted in "thicker", but fogged plates. I used iodine and bromine for the portrait but again the image is hard to see on the plate. The scans are somewhat misleading because I adjusted the white and black points. I was wondering if anyone could offer me some advice on how to improve the contrast of Daguerreotypes? Any help would be greatly appreciated.

Daniel

[Mike Robinson]

I expect you might find a gain in contrast, speed and brightness if you Iodize to first cycle rosy yellow for flat light or full rose magenta for exterior work.

Mike Robinson

[Krokodul]

Hi Mike,

Thank you for your quick reply. I still find it difficult to judge the color of the iodized plate. Are you suggesting to iodize to full rose magenta on the first or second cycle?

Thanks,

Daniel

btw, I will need to order some more plates from you soon

[christian_rice]

I’m pretty sure Mike is referring to the color cycle of the plates, not which iodine pass you are on (if I comprehend the nature of your question). The more color cycles you go through, the thicker the sensitized layer, and the slower and less contrasty your plates will be.

See a thread at http://www.cdags.org/dagforum/topic.php?id=31 for more background.

So that would mean “the first rosy yellow” or “the first magenta” that results from total iodine sensitization that you can examine under light. If you break up the iodine pass into two halves, that is, xx seconds iodine, examine plate color (hopefully it’s yellow), then another xx seconds iodine with plate rotated 180 degrees, examine plate color (you should be approaching the desired color of rosy yellow or rosy magenta Mike refers to). Then bromine, and you can examine the plate again, to find a fairly deepened rose, or bromine a touch more. Then lights out, and iodine once more for 2/3 of the original total iodine time. You can’t really tell the plate color after the final iodine pass, or you’ll be adversely fogging your plate.

To judge the color of the plate, you can have a 40 watt incandescent bulb maybe five or six feet away. Hold the plate so it reflects a whiteboard or white paper, and look at the surface of the plate.

You could also make a test plate with different bromine times, to find at which point your plate is fastest. It’s a curve, and fog is induced beyond a point. Use a small strip of card stock to block bromine sensitization to make a test strip of sorts.

If you wait an hour or two after sensitization to make an exposure, your plate can pick up speed, up to a whole stop. But don’t want after exposure to dev it, as the image is fading away.

There’s lots of places one can set up tests, so it’s good that plates can be reused…

Hope this helps, corrections welcome.

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