[alt-photo] Re: casein history

Evan J Hughes evan at evanhughes.org
Sun Jul 22 09:44:01 GMT 2012

Hi Chris,

    I have had a chance to experiment a little with the gelatine/casein 
carbon tissue and have noticed the following:


    1. the casein does add flexibility to the tissue so any soap/sugar 
can be reduced which helps the tissue to dry out much more thoroughly 
after sensitising.
    2. if the tissue is exposed in front of a hot UV source such as the 
sun or an arc-light, it will be far less likely to melt due to the 
casein; the additional dryness from point 1 also helps here as there is 
much less moisture in the tissue.


    1. the tissue temporary support must either be removable, or very 
thin paper as in development, the alkaline solution needs to be able to 
reach the unexposed tissue in order to allow the backing sheet to be 
removed.  It is possible to pour a tissue onto waxed glass, and then 
remove it as a sheet with no support paper. I have made a print this way 
(with gelatine only tissue) however the dimensional stability of the 
sensitised sheet of tissue is very poor and the image became 
distorted.   If tissue is poured onto a thin transparent support (and 
remains stuck to it), the exposure can be made through the support 
material and the tissue will develop very well in the alkaline bath as 
the unhardened surface is exposed to the alkali directly.  The tissue is 
then mated to the final support after development as in the double 
transfer method.   I have tried this approach too with a gelatine only 
mix and the problem is that the pigment must be ultrafine and of even 
particle size; the tissue is poured onto the transparent sheet and the 
large pigment particles (soot in my case) settle under gravity to the 
lowest point.  This lowest point is now the surface that gets most 
exposure and therefore the image develops with a fine layer of rough 
large pigment particles across its surface.  The problem is compounded 
as when casein is added, the glop takes much longer to gel when pouring 
tissues and so the pigment has much more time to settle out.
    2. When the support paper has been removed and development is in 
progress, the unexposed tissue 'erodes' rather than melts away as the 
alkaline solution dissolves it slowly.   With gelatine only tissue, it 
absorbs lots of water in the mating bath and then the heat of the 
development water melts the gelatine through the bulk of the tissue 
rapidly so the highlight areas lose large quantities of molten gelatine 
in a short space of time.  Thus the print develops quickly.   The casein 
tissue also absorbs water very well in the mating bath (even with up to 
50% casein, water absorption and subsequent final support adhesion were 
not an issue), but then in the development bath, the tissue is already 
saturated with Ph neutral solution so it is only the exposed surface of 
the tissue that can be influenced by the alkalinity.  The print takes 
much longer to develop and the highlight detail development is *very* 
uneven and blotchy.   If the transparent substrate method of point 1 
above is used however, the development would be much better as there is 
no mating bath and the tissue will get its first soaking in the alkaline 
   3. the alkaline bath not only dissolves the transferred tissue, it 
also slowly dissolves the sizing on the paper that the tissue is mated 
too (even though I use gelatine hardened with formalin). If development 
takes too long, the image can start to break free from the paper as the 
size underneath the image is being broken down. I also had problems with 
the pigment that was suspended in the development water stained the 
paper in the areas where the sizing had been degraded.  It may mean that 
a more alkaline tolerant sizing is needed.

Advantage or Disadvantage

1. The alkaline nature of the bath keeps etching away at the print the 
longer it is left, so it does appear to have a contrast reducing effect; 
in my case with thin negatives, this is undesirable, but it could be 
useful for others.

In conclusion, there does seem to be a practical way to make 
gelatine/casein carbon tissue work:

1. pour the glop with very fine and very uniform pigment (such as Indian 
Ink) onto a thin transparent substrate (thicker substrates will degrade 
image sharpness)
2. expose the tissue through the transparent substrate base
3. develop in the alkaline solution (the transparent substrate and any 
sizing on it must be alkaline tolerant)
4. mate to the final support paper using the techniques of double transfer.

   As my soot pigment is course and non-uniform, it does prevent the 
process being unusable unfortunately so I think I will stick to gelatine 
only for the carbon work, but continue with casein instead of gum for 
other printing.    The issues with using the process probably are good 
pointers as to why casein never really took off as an ingredient of 
carbon tissue.

       Best regards,


On 20/07/2012 20:15, Evan J Hughes wrote:
> Hi Chris,
>    Thanks for the heads-up on the book; I will hunt it out.
>     I use soap that is primarily made from olive oil (I make my own 
> soap too so I have plenty).   The key is to use real soap from 
> saponified oil, rather than modern detergents that may say they are 
> soap.   I have also used soap-flakes designed for clothes washing in 
> the past too, however it is getting more difficult to find real soap; 
> the detergents are much cheaper to manufacture and so as consumers we 
> are not being given much choice these days.
>    I use the soap to counteract the effects of the oil in the soot 
> that I grind for the pigment.  The oils and tars in the soot seem to 
> react with the soap to kill all the bubbles in the glop; the result is 
> that it is like pouring liquid silk when making tissues.  If you add 
> soap with a non-oily pigment (or do not add oil), the glop can foam 
> like crazy and does not make good tissue. I assume the availability of 
> high-quality oil-free pigment is one reason that soap-based glop fell 
> out of favour and practitioners turned to IPA for controlling 
> bubbles.   I still use sugar so that the tissues melt easily and 
> develop well at a lower temperature (my sugar:gelatine ratio can be as 
> high as 1:1 too).
>    I poured some gelatine tissues a while ago with acetate as a 
> backing support.  When the tissue dried, it came clean away from the 
> acetate to form a 'true' unsupported carbon tissue.  I have just 
> sensitised a piece of this tissue (carefully!) to see if I can make a 
> print without using any backing paper support.   If so, it may be a 
> route to using the gelatine/casein mix easily.
>      Best regards,
>                Evan
> On 20/07/2012 19:54, Christina Anderson wrote:
>> Hi Evan,
>> I was not researching carbon so did not pay any attention to the 
>> support.
>> The soap in Johnson's patent was in place of the sugar.
>> Hope this helps. My guess would be (as Weston Naef said to me while 
>> we were both sitting in the GEH library researching so I bent his ear 
>> for a bit) that if casein is not included in the carbon formula (or 
>> Fresson for that matter) it was because there was an issue with it 
>> that made it not work as well as other substances. But heck, if it 
>> works for you, pretty soon we'll see Evanotypes!
>> BTW what soap are you using? I think he was using potassium oleate, 
>> if that is the correct chemical name.
>> I don't know if you've researched this book, but it is available at 
>> abebooks.com and is a GEM. Patents for Inventions, Abridgments of 
>> specifications relating to photography.NY: Arno Press, 1979.
>> Chris
>> Christina Z. Anderson
>> christinaZanderson.com
>> On Jul 20, 2012, at 12:42 PM, Evan J Hughes wrote:
>>> Hi Chris,
>>>    Very many thanks for the extract of the patent; I will try with 
>>> alkaline developing baths.   I have found carbon tissue is most 
>>> susceptible to melting/ over softening when the tissue is being 
>>> sensitised or mated to the final support; I use spirit sensitising 
>>> now so do not have many issues, however I could see that tray 
>>> sensitising could be quite alarming if the tissue started to 
>>> dissolve in the dichromate bath.
>>>    Did the patent mention what the tissue temporary support material 
>>> was intended to be?    I use a paper support but I vaguely recollect 
>>> some of the early patents consider using a thin layer of colloid.  
>>> With the colloid, it may be possible to expose from the reverse 
>>> side, through the colloid support, so that the image can be 
>>> developed directly (i.e. the unhardened gelatine is on the opposite 
>>> side to the colloid support film).  A transfer could then be made to 
>>> the final image paper and the colloid layer removed.  If this is the 
>>> case, the tissue does not have to separate from its temporary 
>>> support during the developing.  When the tissue is poured onto a 
>>> paper backing, the gelatine does need to melt in the developing bath 
>>> so that the backing paper can be removed and the development 
>>> completed.   I am intrigued to see how the alkaline bath can 
>>> penetrate well enough through the paper to the unhardened 
>>> gelatine/casein mix in order to allow it to dissolve enough for the 
>>> support paper to be stripped away; I will give it a go though.
>>>    I also noticed the patent says 'Soap, however, is not absolutely 
>>> necessary'.   I use a soap-based glop, but I add soap not for 
>>> pliability (the sugar does that), but to remove the bubbles (yes it 
>>> is counter intuitive!).   Does the recipe also use sugar for 
>>> pliability?
>>>   Best regards,
>>>               Evan
>>> On 20/07/2012 01:28, Christina Anderson wrote:
>>>> Hi Evan,
>>>> Glad you are trying this! Gelatin was susceptible to melting in hot 
>>>> water or weather and casein would help with that, esp. in summer 
>>>> months. Here is part of the patent description that may be of some 
>>>> help.
>>>> My third improvement consists in replacing the gelatine and its 
>>>> analogues in the above compounds wholly or in part by certain other 
>>>> organic compounds having the property of insolubility in warm water 
>>>> but of solubility in some other chemical agent, such as ammonia or 
>>>> the alkalies or salts; and the best substances I am at present 
>>>> acquainted with are the proteine compounds which possess the 
>>>> specified properties, such as caseine, legumine, modified albumen, 
>>>> and their congeners. A pigment compound so formed, and mixed with a 
>>>> bichromate, is sensitive to light; but the picture is not revealed 
>>>> or developed by hot water until a few drops of ammonia or other 
>>>> alkali possessing the like property has been added to the water. In 
>>>> carrying out this part of my invention I form a curd of skimmed 
>>>> milk, as in making cheese, by precipitating the caseine with rennet 
>>>> or by an acid. I collect the curd on a filter, and, after partially 
>>>> drying it by pressure, I dissolve the caseine or curd in dilute 
>>>> liquor ammonia. This solution—which should be as thick as the 
>>>> previously described solution of gelatine in four and a half parts 
>>>> of water—I use instead of a portion of the gelatine solution; that 
>>>> is to say, I take away part of the gelatine solution and substitute 
>>>> in lieu thereof an equal portion of the caseine solution. The 
>>>> quantity so substituted may be greatly varied. Ten per cent of the 
>>>> caseine solution so substituted renders the resulting compound 
>>>> insoluble in water until a certain quantity of ammonia has been 
>>>> added, and twice or three times that quantity does not prevent a 
>>>> workable tissue compound being formed; and in making such a pigment 
>>>> compound I find it best to mix the caseine solution with that of 
>>>> the soap, and add the two together to the gelatine. Soap, however, 
>>>> is not absolutely necessary, as the caseine itself gives 
>>>> flexibility to the tissue, and thus supersedes the necessity of 
>>>> employing the soap...
>>>> Christina Z. Anderson
>>>> christinaZanderson.com
>>>> On Jul 19, 2012, at 11:30 AM, Evan J Hughes wrote:
>>>>> Hi Chris,
>>>>>    I hope to have another go at adding casein to carbon tissue 
>>>>> over the next few weeks, but on thinking about the behaviour of 
>>>>> casein, do you know what the advantage of adding casein to carbon 
>>>>> tissue was thought to be?
>>>>>    My first thought was that it may make the tissue more sensitive 
>>>>> and therefore expose faster, but otherwise, many of the properties 
>>>>> of casein are not necessarily an advantage, i.e. it is important 
>>>>> to have a recipe that develops easily in warm rather than hot 
>>>>> water to reduce issues with bubbling; the unexposed tissue needs 
>>>>> to melt very easily to allow the support paper to be stripped 
>>>>> away.   I do not see how the casein may help with adhesion during 
>>>>> transfer, although it can make a very effective glue.
>>>>>   I plan to try a few glop mixes ranging over 10% to 30% of 
>>>>> casein; have you noticed how much pigment was used in the 
>>>>> gelatine-casein carbon tissues?   I wonder if the pigment quantity 
>>>>> may be very high so that a very thin, high contrast tissue can be 
>>>>> poured; rapid automated manufacture is then much more simple which 
>>>>> would be important for mass-produced tissue.
>>>>>      Best regards,
>>>>>            Evan
>>> -- 
>>> http://www.concretebanana.co.uk
>>> http://blog.concretebanana.co.uk


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