[photolytic]

My basement fuming area is now about 15C/60F and my fisrt iodine fuming time is only 20-24 seconds. I suggest that you may be using too thick a coating although the light golden yellow color is good. By looking at your plates after a partial 2nd iodine fuming you may be surprised at how much more the color has changed after the bromine fuming. You may want to reduce the bromine too.

Are you heating your plates with a blow dryer to warm them up before fuming?

It gets rid of any moisture on the plates as well.

Placing your plates in a Ziploc bag with silica gel before and after exposure is good in humid weather. After only 20 minutes at 19C you should not be experiencing any latent image loss.

[photolytic]

I said above “a yellow magenta after part of the 2nd iodine will give highest sensitivity”.

I suggest you conduct the major portion (say 3/4) of the 2nd iodine fuming under white light.

That way you can see the “final” color of the plate to which I am referring above.

Then to finsh off the fuming, do the final 2 to 5 seconds of the 2nd iodine fuming under a safelight. This will eliminate all fogging caused by white light exposure during fuming.

[photolytic]

Has the temperature in your darkroom gone up?

The fuming boxes may be warmer, which increases halogen fumes concentration.

Try cutting back on the fuming especially the 2nd iodine, for more contrast.

Plate color of yellow magenta after part of the 2nd iodine will give highest sensitivity.

Also the lower mercury temp, even down to 50C, should give you more control with less mist.

You mentioned that you used 9600ws strobes (your plural).

How many and at what distance?

[photolytic]

Andy, Not a problem.

Low cost 400watt power inverters that plug into a car’s 12 volt outlet are available for <$50.

Higher watt inverters are available but they may blow the 20amp fuse unless you clip them to the battery terminals

I bought the 225 array of red LEDs in a 12×12 fixture but have yet to try it out.

I’d be interested in how close it needs to be to the BD plate.

Incident light readings at distances from 2 to 12 inches from the array are 6.2-7.4.

[photolytic]

You mentioned only the cadmium salts in your post so I didn’t give ether advice.

No need to add extra ether.

We never did in the past and several on the forum also agree.

Commercial Collodion already comes dissolved in a 75/25 ether/alcohol solvent.

Just dilute the collodion 50/50 with alcohol. Add up to 60/40 in winter, when the temp is low.

Don’t bother buying Everclear 95% potable alcohol at >$10 a bottle too unless you’re going to drink it. Denatured from Menards is much cheaper ($15/gal) and works just as well if not better.

Artcraftchemicals.com has both Cadmium Iodide and Bromide at approx. $25/oz.

You can even request Potassium cyanide although they don’t list it in their catalog.

[photolytic]

Boy are you one the wrong forum!!!

Try looking on http://www.cwreenactors.com/phorum/list.php?

You’re belching mercury and bromine out of your fume hood and you’re worried about a few 10ths of a gram of cadmium salts in your collodion which will end up in your also toxic silver nitrate bath? I hesitate to ask if you fix your wet plates with potassium cyanide.

First of all potassium bromide is COMPLETELY INSOLUBLE in the alcohol/ether solvent of collodion.

Second. If you have any potassium iodide in your collodion and you add any soluble bromide salt, such as ammonium bromide, to your collodion, it will instantly equilibrate (They called that double decomposition in the old days) to a mixture containing potassium bromide which will begin to precipitate.

KI + (NH4)Br <—> KBr + (NH4)I

AS the KBr begins to precipitate, the equilibrium in the above reaction will try to maintain a the concentration of KBR in solution by shifting the reaction to produce more KBr until the reaction runs out of either potassium or bromide leaving nothing but iodide in the collodion.

Some will tell you to add water to the collodion formula to prevent this precipitation but water too is insoluble in ether and will leave the collodion with a hazy of suspended aqueous KBr solution. After week or so that too settles out (They call it “clearing), leaving the collodion clear but with little or no bromide.

http://www.moderndags.com/DSCN3674.jpg

If you still don’t want to use cadmium salts, which are soluble in alcohol. Your best bet is to use replace all of the potassium iodide/bromide salts with those of non-toxic sodium, ammonium, or lithium (cures you of bipolar disorder too). For examples, see the excellent NaI/NaBr wet plates posted by “Sean”) in the collodion forum above.

You would also help yourself by consulting the excellent collodion advice of longtime collodion and daguerreian expert George Berkhofer.

I made my first wet plates in 1955 and, with the help of my friend George Berkhofer, developed all of my collodion formulae with nothing more than a high school chemistry background so it’s not rocket science.

I can vouch for the excellence of many of the collodion formulas to be found in the Towler’s Silver Sunbeam” and Carey Lea’s “Manual of Photography” or Hardwich’s “A Manual Of Photographic Chemistry”, all of which can be found on-line or as reprints on eBay.

[photolytic]

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[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.

[photolytic]

Looks like a mercury spot caused by a drop of liquid mercury on the plate surface.

They usually form in the fixing bath. Sometimes you can knock the drop off the plate surface before fixing by holding the plate vertically and lightly banging the plate on a hard surface

[photolytic]

Get regular glass.

A case of 100 sheets of 8×10 regular glass costs about $50 from a glass supply company.

Get a glass cutter and learn to cut it down to any size you need.

[photolytic]

Beautiful whole plate Mike.

Is that a clad silver plate?

I believe that previously the width of your clad copper limited you to half plate size.

Did you find a source of wider silver clad copper for your work?

Will you be selling clad whole plates now?

[photolytic]

Rob,

Rob,

Sounds like your gold recovery idea is a good one.

One assumption might be that a gilded wholeplate Dag (356.45cm2) is covered with a monolayer of gold atoms. Actual X-ray scattering measurements I did on Dag plates gilded by Tom Young showed that approx. 5% of the silver atoms on the surface of the plate had been replaced with gold.

The molecular diameter of the gold atom is about 0.288 nm (0.0000000288cm) Approximately 4.297 x10^16 atoms of gold, weighing 14 mg, would fit on the surface of a wholeplate 16.5cm x 21.6cm.

Assuming that your gilding solution contains approx. 1 mg/cc of gold chloride, which is 50% gold, this is equivalent to the amount of gold in 28cc of gilding solution.

Therefore, if you gild with 80cc of solution, there may be approx. 52mg of gold chloride left (65%) in the solution after gilding.

If only 5% surface coverage is assumed, only 1.4mg of gold chloride (<2%) would have been consumed, and a whopping 78mg left in the gilding solution.

That would make gold recovery a worthwhile venture indeed.

[photolytic]

Festus,

Get yourself an infraRed thermometer. Sears has one for about $60.

Shoot for a gilding temp of 60-70C where the solution begins to steam but no bubbles appear.

It helps to have good lighting so you can see what’s happening.

[photolytic]

Festus

No 54 Whatman paper filters faster,and its hard finish absorbs less solution.

No need to age the solution. It’s ready right away.

In fact it’s better to make it fresh and only as much as you need for 1 plate.

Any color in the gilding solution is usually colloidal gold, a very fine precipitate which is less active in the gilding process and will eventually settle out.

If you practice pouring your gilding solution on a level plate rather than using a tray you’ll save lots of money. Approximately 80 ml is all that is required for a wholeplate.

Don’t use your fingers to spread it around as was suggested above.

Get a glass stirring rod. It’s much cleaner and won’t contaminate the solution

By the way I liked Mr. Dillon’s first deputy, Chester, with his gimpy leg.

[photolytic]

Ken,

Your plater wouldn’t be named Dr Frankenstein would he?

Festus,

Sometimes a “wee bit” more polishing isn’t enough, especially if the image was gilded.

I usually double or triple the amount of repolishing to be sure.

Even if you don’t see a ghost of the old image during fuming you may get one after developing the new image. The ghost isn’t from a latent image in the ordinary sense, in that it is usually a negative shadow, perhaps due to traces of mercury or surface roughness on the plate, either of which can interfere with subsequent fuming.

Mercury on the silver surface or residual roughness from the previous image can make the silver more reactive to the halide fumes, imprinting the plate with a pattern of thicker silver halide in the highlight areas of the previous image, which may make them slightly less photosensitive.

Ken used to advise “burning the plate” which involves heating the plate on a hot plate to 350F for a period of time to evaporate any traces of mercury. If you do this always do it outdoors.

[photolytic]

Well said Rob,

One might also add the caviate that not all platers will give you what you ask for.

Witness the sad story told by Race in San Diego where he paid $400 for a few sixth plates with only minimal silver.

Trust in a plater recommended by another Daguerreotypist is usually safe, but if you have to find a new plater, good luck.

First, choose a plater with XRF thickness analysis equipment.

The coulohmb thickess meter which platers used to use puts a hole in the silver layer.

Pre-weigh the polished copper plates to verify the work of your plater.

Be upfront about this, telling the plater what you have done.

Supply him with a list of your original plate weights beforehand so he can verify your data.

Call this quality control.

Be sure to put in writing, on the invoice, that if his work does not meet your thickness specifications in the center of the plate by a reasonable margin (say 50%) you will send the plates back to him for additional plating at his expense.

Over a period of 10 years I have only had to do this with two platers and it has only taken one such experience for the plater agree to comply with your requests.

I actually brought my digital balance to their lab and weighed the plates there to prove my point.

[photolytic]

http://en.wikipedia.org/wiki/Faradays_laws_of_electrolysis

Faraday’s 2nd Law of Electrolysis – For a given quantity of electricity (electric charge), the mass of an elemental material altered at an electrode is directly proportional to the element’s equivalent weight. The equivalent weight of a substance is its molar mass divided by an integer that depends on the reaction undergone by the material.

Mathematical form

Faraday’s laws can be summarized by

m = (Q)/F) x (M/z)

where

m is the mass of the metal deposited at an electrode

Q is the total electric charge passed through the metal solution.

F = 96,485 C mol-1 is the Faraday constant

M is the molar mass of the metal which is 107.88 gm/mol for silver

z is the valency number of ions of the metal ( 1 in the case of silver)

Note that M / z is the same as the equivalent weight of the metal deposited.

For Faraday’s second law, Q, F, and z are constants, so that the larger the value of M / z (equivalent weight) the larger m will be.

In the simple case of constant-current electrolysis, Q (coulombs) = electric current in amps (coulombs/second) x time t (seconds)

For a 4 x5 inch plate (area 129.032 cm2), a 10 micron (.001cm) layer of silver (10.49 gm/cc) weighs .000134535 grams.

.000134535 grams of silver contains m / 107.88 or .00001254677 moles of silver

which when multiplied by Faraday’s constant (96485 Coulombs/mole) will require 1.210575 coulombs of electircal charge.

Assuming a reasonable plating time of 5 minutes or 300 seconds, a current of .00403525 amps or 4 milliamps will be required.

Therefore you need to get yourself an accurate milliamp meter to monitor this current plus a DC rectifier or battery current source.

[photolytic]

Congratulations Richard. That is a great image. Hard to tell it’s Becquerel and not mercury.

It’s obvious that the digital age has not diminished your ability to find the best exposure the old fashioned way. Keep up the great work.

I agree with Alan’s suggestion. Perhaps we need another topic like “My latest successful Dag” for images like Richard’s and another like “What went wrong here?” for blank plates. One of the most frustrating experiences on this forum is inappropriate posting of great and faint images side by side. It would be helpful if more posters stayed on topic a bit more.

[photolytic]

Here is another group of Dags by Hurlock and Robinson not shown

 

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[photolytic]

Jason and Alan,

If you cover the back of your plates with platers tape before you send them to be electroplated you will not get any silver on the back.

http://www.mcmaster.com/#76095a138/=3q6rd4

This tape is resistant to cleaning solvents and will not contaminate the platers silver bath. It comes in 3 inch wide rolls and should be applied with a slight overlap.

It is easily pealed off leaving a clean copper surface with no adhesive residue.

For dip plating Ake Hultman in Sweden has successfully tested a commercial brush silver plating solution on his electroplated Dag plates.

http://www.goldn.co.uk:80/products/silver_plating_soln.htm

According to the manufacturer their solution leaves 0.6 microns of bright silver on the plate. This can be increased to 2-3 microns of bright silver by applying a 2-3 volt potential. No silver (or copper) anode is required.

“Dear Mr. Hultman,

Thank you for your enquiry. I’ve tested our silver in a tank and it

plates well bright up to a thickness of 3 microns with the minimum required buffing by hand to give the final flaw-free appearance.

For tank coating, I recommend 2.5 – 3.0 volts with a carbon or platinised titanium anode and constant agitation. The solution may be operated at room temperature.

Best regards

Richard Palmer

Director”

[photolytic]

Ken,

I found nothing wrong with the balancing of the equation nor did I have any doubts as to the former abilities of the “Renaissance Man” to carry out many chemical procedures.

I was concerned that there was considerable risk if these formulae were passed along to unsuspecting chemical neophytes.

As you wisely cautioned there are dangerous articles out there like Mark Baczynsky’s “How to Make a Daguerreotype” that contain instructions for making Dags, which are “dangerous and must not be followed”.

I consider a procedure for making bromine to be too dangerous unless performed by an experienced chemist in a commercial fume hood with good ventilation.

Have a good trip to Paris and take lots of pictures of our Dags.

John

[photolytic]

Despite requests from this forum for more input from experienced chemists, I have hesitated to offer suggestions for the synthesis of dangerous chemicals like bromine, because I do not believe photographers with limited chemical knowledge should be encouraged to risk their health and lives making something that they could purchase, even at considerable cost.

Both Ken and Jason have offered good suggestions for modifying the Bromine synthesis reaction. The use of manganese dioxide @$4/lb is certainly preferable to the more costly KBrO3 as an oxidizer. However since no temperature requirements are mentioned in the referenced literature one may assume that more heat and /or an excess of one of the reagents may be necessary drive this reaction to completion.

I am a bit disturbed by the reliance on tables of chemical quantities for reaction recipes. Perhaps I am wrong but it appears that limited attention is being paid to the principles of chemical stoichiometry here. Unless one has first mastered the skill of calculating reactant quantities from the molecular weights and concentrations of the components in a balanced chemical reaction, there is a very real danger that the chemical experimenter may make the fatal error of assuming that “more is better”. This could be a real danger in the synthesis of a dangerous material like bromine.

[photolytic]

Hi Irv,

Your estimates of the spectral sensitivity of iodized Dag plates were based upon absorption coefficients for silver iodide published in the international critical tables?

You used a Beckmann DK-2a spectrophotometer to measure total D-plate spectral reflectance over a wavelength range of 380 to 700nm. Since reflectance maxima were around 425nm you concluded that maximum spectral sensitivity was also at 425nm. Can you use a spectrophotometer to make the same measurements on a D-plate with an AgI/AgBr coating?

Skiadnikiowitz et al measured their AgBr/AgI spectral sensitivity with a spectrosensitometer equipped with a grating spectrograph. According to their description, wet plates were placed behind the exit slit of the monochronometer, and a step wedge traveled synchronously with the wavelength adjustment of the monochronometer in steps of 10nm. To calibrate the output of the spectosensitometer, they measured the relative magnitude of the radiant exposure as a function of wavelength and varied exposure times with the wavelength to achieve constant exposure energy for each wavelength. Could this be done with D-plates?

All the best,

John

[photolytic]

No number label on the cap Andy. It was made long before recycling was popular.

The cap looks like the ones you posted with three concentric circles on the top.

The cap is hard and not transparent. It’s probably number 4, ABS (acrylonitrile, butadiene, styrene) which is relatively resistant to aqueous acids, alkalis, concentrated hydrochloric and phosphoric acids, but is attacked by concentrated sulfuric and nitric acids.

[photolytic]

Here’s the Fisher Bromine bottle. I had to tape the label back on but it’s ok otherwise.

The cap has a white plastic liner (teflon?) stained a light orange from the bromine.

 

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