Overdeveloped Becquerel Daguerreotypes

[simonechoulle]

Hello

We’re are very beginners in Dag. We went to the bry-sur-marne exhibition and to the Marc Keuren’s class where he shows us Mercurial Dag. A Wonderfull guy !

We made some tests with mercure but is unsafe in our little parisian flat, so we started with becquerel and we like the light as a developper.

After many tests to find the good exposure and the good iodine layer for us, we are in front of another problem. After the hyposulfite bath, we saw some areas like hardened iodine maybe due to an overdevelopment.

Do you think those clear stains are a result of overdevelopment?

We used :

2 layers of rubylith and the sun.

Electroplated plates

Coating in the first cycle and the colour is near the purple, magenta/purple

Datas for the first dag

EV15

f11 – 5 minutes

1h dev under 2 layers of rubylith, the image begins to appear after 5 minutes

Datas for the second dag

EV15,5

f16 – 3,30 minutes

2h dev under 2 layers of rubylith, the image begins to appear after 15 minutes

Thanks for your help !!

Simone Choulle

[Pobboravsky]

Hi Simone,

For beginners, these images are remarkably good. My congratulations.

I think the first image is overexposed in the camera since the image began to appear in just 5 minutes of Becquerel development.

The second image seems to be correctly exposed in the camera. Increasing the Becq. development time will eliminate the blue tone.

To arrive at the correct exposure you might consider making a series of increasing exposures on a single plate. First expose the entire plate for say one minute, push the dark slide in 2-cm and continue the exposure for another minute. Repeat the 2-cm movement and 1-minute added exposure until the dark slide covers the entire plate. After Becq. dev. examine the image and select the exposure time that gave the best image. Expose the next plate for the best-image time.

To see the effect of Becquerel dev. time on the appearance of the image, a plate given the correct camera exposure can be given a series of Becq. dev’ment times by a similar method. You can then select the best development time by examining the final result.

Before iodizing the plate must be very clean to avoid the non-uniformities in the image.

You have made a great start on your daguerreian journey.

Bon chance

Irv

[greg7mdp]

Indeed, these are excellent plates for a first try, and Irv’s advice is excellent and will help you find the best exposure. Those stains you have are unusual. Two thoughts. Is your plate too close to the iodine when you sensitize? And do you leave the plate in the hypo long enough to make sure you have removed all the unexposed silver halide?

Bien le bonjour à Mark, et je vous souhaite encore meilleure réussite pour vos prochaines plaques.

gregory

[Festus]

Good thought about the hypo. I usually leave my plates in the hypo for 15-20 minutes.

[photolytic]

15 minutes in the fixer may be too long, even for heavily coated Becquerel plates.

3-5 minutes should do it if your hypo is fresh and of the correct strength.

After 15 minutes you may see some cloudy precipitate in the fixer.

That may be image particles dislodged from the surface of the plate.

[Festus]

I did an experiment. Sensitized a plate to the first yellow. Then walked outside, but still in the shade. The yellow is very visible. Put in the fixer, and you can actually see the yellow (iodine) slowly disappear from the plate. Took about i5 minutes to look like a polished silver plate again. It was a fresh tray of fixer. Maybe I mixed it too weak? 15 grams of Sodium Sulfate and 15 grams of Sodium Thiosulfate in 1000 ml of water?

[simonechoulle]

Bonjour !

So i made new tests in accord with your advices.

First, I clean better my plates, but I have to improve !

Second, I increase the Becq. development : 5 hours to day light

Result, the clear stains disappear !!!!! And the blue tone faded !

So Irv you were right and I thank you for your great help !

The test…the camera moved when I put the film holder, so the focus is pityfull!!

The plate was an old gilded test that I tried to polish again, I think I can improve.

Does anyone have an idea how to erase all from a gilded plate ?

Data for the test :

Iodine magenta/purple first cycle

EV11

f5,6 – 20 minutes

Fix 8 minutes

5h dev under 2 layers of rubylith, the image begins to appear after 8 minutes only the white background

Gilded

The coat of the virgen is made of red velvet !

Next time I’ll post a dag not a test !

Thanks for all

Simone

[Festus]

Simone. That may be a test dag, but it’s still very good.

[Pobboravsky]

Hi Simone and Festus,

Festus, perhaps you meant sodium sulfite rather than sulfate. I don’t know the effect of sulfate on the time it takes to remove silver iodide from a plate. Sodium sulfite should be used with sodium thiosulfate in a fixer. The image of a Becq. plate consists of metallic silver particles of various sizes — all of them quite small. Fixing a plate for a long period of time will first dissolve the smallest silver particles and with enough time reduce the size of even the largest particles. In other words it will weaken the image. An

Quote:

Iodine magenta/purple first cycle

should clear in under a minute and can be kept in the fixer for 2 minutes. Adding sodium sulfite reduces the rate of dissolution of the metallic silver particles.

I very much agree that the image is very good. You are making remarkable progress.

When you iodize the plate does the color of the iodized plate show the same non-uniformity as you see in the final image around the edges? If so it provides an early warning that the edges are not clean. I wonder if fixing the iodized plate is a way of cleaning the plate; after rinsing in distilled water and drying – re-iodizing the plate will show if the color of layer is uniform right to the edges. If it is uniform you can use the plate in the camera.

Good Luck, I look forward to seeing continued progress.

Irv

[Festus]

Oh geeez! I looked at the bottle closer. and I received Sodium SOLFATE from Photographers Formulary. Don’t know if that was my mistake or theirs, but no matter. Pobboravsky, I’m glad you caught this. No telling how long I would have been fixing with this wrong mixture and never noticed. Much Thanks! I’m off to order the right stuff.

[drdag]

Mistakes like that is how things get discovered….

[Mercury]

… and the lessons learned by mistake are far more likely to be remembered than the lessons learned by success…

Merci Simone, Irv, drdag, and Festus

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