Hand Made Azo? Is it possible?

[Photo Engineer]

Where is Jim Browning's website?

Here is one of his sites.

http://www.dyetransfer.org/images/DyeTran.pdf

PE

 

[Photo Engineer]

An Azo - like paper that can be made in a low tech workshop would be great.

Can a warm-black ( Illustrator's Azo ) or brown-black ( Athena ) be done ?

Now you've got me thinking about handcoating from old receipes....
Dassonville ?

Having a supply of Ilford FB for normal work, and home-coated special paper would suit me down to the ground.

I have done a warmtone version of Azo which is done by using a very unusual precipitation which will be discussed at my workshop (unabashed plug there).

I know how to do the same thing with a Brovira or Kodabromide formula, but it requires a lead salt to achieve the same effect with bromide as you do with chloride, and no one wants to ship lead salts today, nor do I especially want to work with them. I am working on an alternative.

See my next reply.

PE

 

[Photo Engineer]

I've been reading the papers all took a drastic turn for the worse once cadmium was eliminated from the formulas for emulsion. That said, the new formulas you are working on, can you also by your own choice add a bit of cadmium if you wanted? Cadmium is not the fearsome thing so many people make it out to be.

Aggie, you are correct. In fact, Cadmium was used in some of the papers that were discontinued by EK in the 60s that had that warm rich golden look. I have been told that this was done by judicious use of cadmium salts.

I have plans to do exactly the experiments you allude to and hope to have some results in hand by the workshop. Unfortunately, peoples fears about Cadmium make its availability rather restricted. For example, warm tone papers often relied on Lead salts, but I cannot get any Lead salts shipped to me so far.

I will be trying Cadmium. Some sources will ship it.

So yes, I'll have a list of metal salts to add to the emulsions to get varying effects. This will include suggested levels and methods of addition for varying effects which include contrast control, tone control (warm, brown, reddish, blue black and etc), latent image keeping, reciprocity failure control, and raw stock keeping.

I will also include some organic chemicals that have the same effect.

I must add that some of the things I have tested, don't match the results claimed in the old textbooks from the 20s to 40s. I also must add that each chemical acts differently with different emulsion types.

PE

 

[Aggie]

Hope you are using distilled water for your tests. With all the chlorine and especially flouride in todays water supplies it would have a marked difference. Thsoe additions didn't come about until well past the 20's

 

[Photo Engineer]

Hope you are using distilled water for your tests. With all the chlorine and especially flouride in todays water supplies it would have a marked difference. Thsoe additions didn't come about until well past the 20's

Yes, Aggie, I use nothing but distilled water.

You can actually precipitate a fair amount of AgCl just by adding silver nitrate to city water. In fact, you cannot wash an emulsion in city water as suggested in the old text books. You could gradually 'convert' to a chloride if you wash long enough. Of course, in practice this is not likely to happen, but it is an item of concern.

I have to keep a large quantity of refrigerated distilled water on-hand for washing emulsions. That is one reason most of my work is unwashed.

And, BTW, I have gotten several e-mails and private messages asking if that is really 90 grams of water or 90 ml of water in the formula that I posted.

I use gravimetric measure for everything in the formula, so it is 90 grams of distilled water.

At the end, I have a total weight that I can use for density calculations as well as changes in weight if I wash an emulsion or add addenda.

So, all emulsion work in my lab in on a gravimetric basis.

PE

 

[Kirk Keyes]

For example, warm tone papers often relied on Lead salts, but I cannot get any Lead salts shipped to me so far.

I will be trying Cadmium. Some sources will ship it.

Ron - have you tried some of your local chemical supply houses? I'm sure Rochester must have some. You may be able to just drive over and explain your usage so they don't think you are making meth or something illegal and then drive home with some.

Lead's not that bad - we all drive around with several pounds of it in our cars everyday. Both the metal and some sulfate even.

I don't really know anything about Rochester specifically, but these guys look like they will know who to call (it looks like they don't carry chemicals themselves):
Laboratory Product Sales
1665 Buffalo Rd, Rochester, NY
(585) 247-4720

Kirk

 

[Photo Engineer]

Ron - have you tried some of your local chemical supply houses? I'm sure Rochester must have some. You may be able to just drive over and explain your usage so they don't think you are making meth or something illegal and then drive home with some.

Lead's not that bad - we all drive around with several pounds of it in our cars everyday. Both the metal and some sulfate even.

I don't really know anything about Rochester specifically, but these guys look like they will know who to call (it looks like they don't carry chemicals themselves):
Laboratory Product Sales
1665 Buffalo Rd, Rochester, NY
(585) 247-4720

Kirk

Kirk, thanks but I do plan on trying some alternatives first. Better something like cadmium than lead, don't you think? There are a few tricks that can be used to avoid Lead Nitrate.

PE

 

[Kirk Keyes]

Better something like cadmium than lead, don't you think?

No, I think they are pretty much equivalent as far as safety goes - Current EPA drinking water standards can be found here: http://www.epa.gov/safewater/mcl.html#mcls
The limit for cadmium is 0.005 mg/L and lead is at 0.015. (The actual goal for lead in treated water is none, but the action limit is higher than for cadmium.) But that's not much difference really.

In air, the OSHA Permissable Exposure Level (PEL) has an 8-hour Time Weighted Average (TWA) of 0.005 mg/m3 for cadmium. For lead it is 0.005 mg/m3 as well. (I believe those are current values.)

So not much difference from a hazard point of view from the numbers I find.

But you may have other overriding reasons based on function in your formulations.

Kirk

 

[tdeming]

And, BTW, I have gotten several e-mails and private messages asking if that is really 90 grams of water or 90 ml of water in the formula that I posted.

I use gravimetric measure for everything in the formula, so it is 90 grams of distilled water.

At first I thought this was meant as a joke..

Since the density of water is, by convention, 1.0 gr/ml, it really doesnt matter, eh?

Since it's easier to measure out water volumetrically than gravimetrically, I'd prefer to go with the volume measurement.

Cheers

Tim

 

[Silverpixels5]

At first I thought this was meant as a joke..

Since the density of water is, by convention, 1.0 gr/ml, it really doesnt matter, eh?

Since it's easier to measure out water volumetrically than gravimetrically, I'd prefer to go with the volume measurement.

Cheers

Tim

Water is only 1 g/ml at 20C, so it changes with temperature, and if there is anything dissolved in the water then the density will change slightly as well. So volumetric measurement really isn't that reliable...esp for QC stuff. Will it matter? Probably not...but there are less variables for error when you do everything by mass. Mass is always conserved (unless you're doing nuclear stuff)...volumes are not.

 

[Photo Engineer]

At first I thought this was meant as a joke..

Since the density of water is, by convention, 1.0 gr/ml, it really doesnt matter, eh?

Since it's easier to measure out water volumetrically than gravimetrically, I'd prefer to go with the volume measurement.

Cheers

Tim

Ummm, that is not exactly correct as it is temperature dependant.

Also, the density of the emulsion is not 1.000 so it is important to keep track of the density of the emulsion so that I know the Kg/mole of silver for coating purposes.

PE

 

[Photo Engineer]

Water is only 1 g/ml at 20C, so it changes with temperature, and if there is anything dissolved in the water then the density will change slightly as well. So volumetric measurement really isn't that reliable...esp for QC stuff. Will it matter? Probably not...but there are less variables for error when you do everything by mass. Mass is always conserved (unless you're doing nuclear stuff)...volumes are not.

Well, another point here should be mentioned.

If you are weighing out 1 g of solid and 99 g of water, this is easier and more accurate than measuring 1 g of solid and 99 ml of water. Seeing the meniscus in the graduate cylinder is not easy. Using a volumetric flask is better but expensive. Using wt/wt measurement is much much easier.

Most gravimetric measurement is one order of magnitude better than volumetric measurement. After all, how often do you see graduate cylinders marked in 0.1 or better still 0.001 ml divisions? I can buy scales and balances that can do this. It sometimes is quite useful in emulsion making.

So, I find it handy.

PE

 

[tdeming]

Most gravimetric measurement is one order of magnitude better than volumetric measurement. After all, how often do you see graduate cylinders marked in 0.1 or better still 0.001 ml divisions? I can buy scales and balances that can do this. It sometimes is quite useful in emulsion making.

PE

Hi PE,

Not to be picky, and you are more than welcome to use any technique you like, but analytical chemists will always use volumetric glassware to measure out liquids with high accuracy and precision. You can always correct density for temperature effects if you are working at high (or low) temperature. I would imagine you will get much more error in your weight measurement due to evaporation and loss of material upon transfer than you would by delivering from a buret or pipet, but then again if you are using a graduated cylinder, you're never going to be very accurate in measuring volume. Volumetric glassware is also not that expensive compared to a good analytical balance. I tend to agree with silverpixels that the errors you get probably wont make much differrence as long as your scale is large enough.

have fun mixing.

Tim

 

[Photo Engineer]

Hi PE,

Not to be picky, and you are more than welcome to use any technique you like, but analytical chemists will always use volumetric glassware to measure out liquids with high accuracy and precision. You can always correct density for temperature effects if you are working at high (or low) temperature. I would imagine you will get much more error in your weight measurement due to evaporation and loss of material upon transfer than you would by delivering from a buret or pipet, but then again if you are using a graduated cylinder, you're never going to be very accurate in measuring volume. Volumetric glassware is also not that expensive compared to a good analytical balance. I tend to agree with silverpixels that the errors you get probably wont make much differrence as long as your scale is large enough.

have fun mixing.

Tim

Tim, holding an emulsion at 60 deg C for one hour does lead to a lot of evaporation, but measuring the volume of an emulsion at the end is virtually impossible in the dark and with an opaque liquid. These are additional considerations when it comes to weighing the emulsion rather than measuring volume.

I guess when you get right down to it, after 30+ years of thinking of emulsions as X kg / mole or so many Kgs or Gs of emulsion, I never think in terms of liters of emulsion on a practical basis, and I have outlined all of my current thoughts here and above.

Again, I repeat that volumetric measurment is not as precise or as accurate as gravimetric as any analytical chemist will tell you. Yes, a burette or a volumetric flask are very precise, but only at the ml level with the burette and only on premeasured volumes with the flasks. And, when you have clear liquids measured at one temperature in the light.

My measurments have to hold true for a solid and a liquid (the gelled emulsion and the melted emulsion over a range from 10 deg C to 60 deg C) which will not work volumetrically. Sometimes I have to dump in hot water.

This may seem odd to you, but it is an integral part of this branch of engineering. It is the only way to achive precise measurements.

PE

 

[tdeming]

PE,

Please dont overinterpret what I've wrote. My original post only referred to measuring out *water*, and at a single temperature. Certainly if you are going to measure out solutions/suspensions/gels, etc, and then heat and cool your samples, it would be pretty much impossible to do this volumetrically and you'll have to make do with whatever you can.

For the record, I have taught analytical chemistry in the past, and have many colleagues who do so now. I'm pretty sure all of us would agree to measure out water volumetrically if we needed a very accurate measure, and this is what we teach our students. I have burets in my lab that will deliver 50 mL with 0.1 mL accuracy. But bear in mind, I'm a scientist, not an engineer ;-)

Tim

 

[Photo Engineer]

PE,

Please dont overinterpret what I've wrote. My original post only referred to measuring out *water*, and at a single temperature. Certainly if you are going to measure out solutions/suspensions/gels, etc, and then heat and cool your samples, it would be pretty much impossible to do this volumetrically and you'll have to make do with whatever you can.

For the record, I have taught analytical chemistry in the past, and have many colleagues who do so now. I'm pretty sure all of us would agree to measure out water volumetrically if we needed a very accurate measure, and this is what we teach our students. I have burets in my lab that will deliver 50 mL with 0.1 mL accuracy. But bear in mind, I'm a scientist, not an engineer ;-)

Tim

I think I was not overinterpreting as much as I was overexplaining.

It was due to the lack of knowledge on the part of a lot of people as to why things work some ways in one field and another way in another field.

And, too many myths about photograpic science abound on the internet.

So, I'm compulsive about putting correct or complete information out there along with reasoning behind it sometimes.

The bottom line is that we are both right but differ due to a materials handling problem that the readers might not appreciate and so I felt it might be useful to present the overexplanation.

PE

 

[Kirk Keyes]

I have burets in my lab that will deliver 50 mL with 0.1 mL accuracy. But bear in mind, I'm a scientist, not an engineer ;-)

Another scientist here - but I would recommend for precise measurements that gravimetric weighing of water or other solvents can be more accurate. You often can weigh the liquid in an enclosed container which will decrease the error from evaporation that one can easily see if your balance is sensitive enough.

I use this technique to check the calibration of adjustable pipettes where I have to measure down to 0.1 mg levels in order to calibrate a 1 mL pipette - to 0.01 mg for a 10uL pipette.

Grad cylinders and even burettes can be pretty crude compared to making measurements by weight with a good balance. Especially when it is dark...