Troubleshooting

[Jon Lewis]

I hope this topic will end up being a useful, especially for those who are just learning. It’s my intent that everyone put their daging woes here in order to build a convenient list of what can go wrong and hopefully, how to fix it.

I just dried off a becquerel daguerreotype and noticed that during the drying the well exposed areas of the image went from a slightly warm color in the water to a blue when dried. It also looks like the image was fogged a little. The only thing I can think of that might have been a problem is heat. When I pulled the plate out from under the rubylith, it was so hot I had to wait a while before I could pick it up. I remember someone saying that it would fog a plate if it got to hot, would it also turn it extra blue? Or is that another problem all together.

The was sensitized it over iodine until the second red. The scene metered 13 EVs @ ISO 100 and it was exposed for 3 minutes at f/4.7. Developed for 3 hours under rubylith and a 200 watt light at a distance of about 10 inches. Fixed in ammonium thiosulfate and washed in distilled water.

I’ll appreciate any thoughts you might have…

[photolytic]

Jon,

This problem can occur when Daguerreotypes are overexposed and underdeveloped.

These images appear to be normal when viewed under water which has a higher refractive index than air. However, when dried, the image may be pale blue in color and are almost invisible under normal viewing conditions.

When examined under a scanning electron microscope at 2000x magnification, the images of these daguerreotypes consist of uniformly small particles less than 0.1 microns in diameter. These particles are so small that only the shorter, blue wavelengths of light are refracted properly. Gilding will not correct this problem but coating the image with a layer of varnish having a high refractive index will make the image more visible.

Normal, fully developed, Daguerreotypes have image particles that are about 1 micron in diameter, large enough to refract the full spectrum if visible light. See “Warming up to cold Mercury” in the resources section.

[Jon Lewis]

Thanks for the info! I had set 3 hours as my standard development time to get neutral color images when I was using pure silver plates. Now I have some silver plated copper plates that have a much better polish and are much more sensitive. The exposure above was two stops under what I had done in the past but it looks like it’s still too long. I changed one variable and everything else goes down the tubes! 😆

I’m also constructing a device to cool my plates during development. I’ll post pictures when it’s done.

[Jon Lewis]

Here’s a scan of the offending dag:

[CasedImage]

So for plate cooling in becq. development this is what I came up with for my plates, which are thin clad plates so are probably easier to cool. The frame is made of black acrylic sheets so it would have some light trapping aspects. The back of the plate remains exposed so it can cool down in the sun but because of the stepped frame, light can’t get to the front of the plate. It worked very well, though working with strange modern materials the frame itself wasn’t the most well polished production, more of a prototype.

It can’t be seen in the images but under the rubylith I bevelled back the acrylic so it wouldn’t cast a shadow. The top part of the frame that has the rubylith is two sheets of acrylic with different sized windows to give the ledge which the plate sits on.

www.CasedImage.com

[Jon Lewis]

Thank you for posting those images Alan. It’s great seeing what other people use. I use a 4×5 film box with a hole cut in the top that’s then masked with rubylith. Not pretty but it works. Though I may borrow some of your design (with some modifications) to reduce the heat on the plate. The 16 gauge copper absorbs so much more heat than the 24 gauge silver did.

I played around with different times when using the pure silver plates and came up with 3 hours as a time that would give me a good neutral tone. It’s no longer the case now. Is there a way of telling when a becquerel dag is done developing besides trial and error? Some sort of magic sign? Peaking?

[CasedImage]

The main indicator I found that if it wasn’t looking promising in the first 10 mins then it wasn’t going to be a great plate and thus maybe not worth worrying about too much. It is hard though peering though the rubylith to decide what is underdeveloped and what is over developed. Most of my development times were one hour sometimes 2 or 3 if I was keen. I must admit so far with mercury I haven’t achieved the whitest whites that I got with Becquerel (see attached). But as the family motto says – ” Do and hope “

www.CasedImage.com

[drdag]

Now it’s light here in blighty, I have dusted off the gear and started making the new series of images. I have noticed a brown sheen where the blacks (IE no silver Iodide) are meant to be.

I thought that it maybe the 4 month old Sodium Thiosulphate solution that I had. I tried some Ilford fixer which worked, but I still had the brown sheen. It is not something that I have experienced before. The only other thing is that I Iodize to the first Yellow (usually about 30-40 secs)Any Ideas?

The image is a little less brown in real life, but pic. taken under tungsten with AWB. It should all be black like the central patch.

Interestingly both the old Sodium Thiosulphate and the fixer stained a plate slightly by just leaving half of it in the tray, standing up.

I have no new Sod.Thio. until it comes later in the week.

 

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