Importance of gilding for durability

[daveL]

Hi all, i have a noob question for you!

Will B-Dags properly mounted behind glass have limited lifespan if not gilded?

Does anyone have any experience on that?

Any opinion on this is much appreciated!

All the best,

Dave

[jgmotamedi]

I have come to doubt the worth of gilding in Becquerel plates. Originally I gilded my Becquerel plates because everyone else told me it was worthwhile, and added to the beauty and durability of the plates. However, looking at the hundred+ Becquerel plates I have made in the past years, I see that those which I did not gild are generally more neutral and tend to have better tonality. Those which I gilded tend to be too blue or yellow or even green, and seem to be more contrasty. Perhaps it is just a skewed sample, but my current prejudice is to skip gilding for Becquerel plates. If properly mounted I don’t see why they wouldn’t last as long as a gilded plate. Really the main problem with not gilded plates in my view is that they are much harder to dry without marks. A drying agent helps, but it is still a challenge.

Note that this does NOT apply to mercury plates; Gilding appreciably improves the appearance of mercury developed plates.

I am sure that others will disagree.

[jgmotamedi]

Really? No one is going to argue with me?

[Mercury]

Well, I can’t really call this an ‘argument’ jgmotamedi, (I’m sure we can find something to argue about… we’re talking about making daguerreotypes after all!) but here’s an experiment I’d like to pose for both B-Dag and M-Dag members:

I have noticed, in my own experience, that when a mercury-developed (M-Dag) daguerreotype is dried before gilding, the image is incredibly fragile. A light finger-wipe will nearly erase all trace of the image.

Now… an experiment: After drying the ungilded M-Dag, wipe it with your finger (in a nitrile glove, of course.) My guess is that the damage will be severe. THEN, take that same plate and re-wet it, and then re-dry it as per your usual process. Please tell me if the same finger-wipe test, re-applied, doesn’t tell you that the image is MUCH more durable than it was in resisting the first wipe.

This is a completely subjective test, since you can not gauge your finger pressure precisely for each wipe. But… given all your chances to make everything the same… what do you observe?

Barger and White note that ungilded plates tend to increase in durability over time, and I have found this to be true. What they don’t say is whether image durability can be enhanced quickly by simply re-wetting and re-drying a non-gilded plate.

I can’t say much as to the effects of gold chloride gilding on the image quality of a Becquerel plate, but this test might lend some knowledge to Jason’s question as to whether gilding is really necessary for the Becquerel Process.

Respectfully,

[jgmotamedi]

Thanks for arguing!

You have proposed an interesting experiment Ken, I will try it an let you know how it works with Becquerel plates, or we can try it when we meet up. In any case, Becquerel plates seem to me to be much more fragile than mercury developed plates. It is often hard to remove all traces of an exposure on a mercury developed plate. It is much easier to do so with a Becquerel plate. In fact, I have watched as a student once washed the image off the surface of a plate with a stream of water.

[photolytic]

There is no reason Bdag images should harden with time as they contain no mercury.

I’ve had some for several years and they are still fragile.

Barger and White attribute the mDag hardening process to a change in the mercury to silver ratio of the Amalgam. Over the years the amalgam continues to lose mercury through evaporation so analysis of very old ungilded Dags showed there was very little mercury left in the image.

Dentists who used to use Mercury Amalgam to fill caries were also familiar with the hardening process. The process is speeded up by heat normally used in the Dag drying process.

Ken you should try drying an MDag without heating to see if the same hardening occurs.

Wash the water off the Dag with alcohol first and let it dry at ambient temperature.

[Mike Robinson]

Hi all,

 

In response to the lifespan of un-gilded daguerreotypes. Gilding does offer greater protection against tarnish. The image shows a comparison between Hg developed plates, one untoned, the other toned. Both placed in a desiccator and exposed to weak Hydrogen Sulfide gas for 4 days.

You could do the same with a mashed up hard boiled egg.

best

 

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[drdag]

I rarely gild my B dags anymore, unless I want warmth. I can get quite a warm day with experience now though.

A few comments,

B dags that have sat around a while in my opinion are more difficult to polish.

Also,if they have been developed for a long time the image is more ‘ingrained ‘ into the plate.

I have never seen an image wash off under a stream of water , I use a air compressor at up to 80psi and I cannot damage my images with this.

Finally if you pull the plate out of the distilled water washing tray stand it at 80 degrees angle in an empty tray , pour boiling distilled water on it , lift out quickly and blow it dries without watermarks every time.I have masks and glass all ready for a keeper, I heat them up a bit and seal instantly if I want it to last.

[Author]

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