Since a very simple test of Ilford MGIV shows that there is a reducing agent (developing agent) in the coating. It is so simple to run. But, Simon Galley has said that there is no developing agent present.
So, something is there that acts as if there were a developing agent present whether that was the intent or not. The paper will develop images with nothing other than alkali. Kodak papers do the same, but many other papers do not.
Someone ran some tests on another Forum with MGIV, there is a weak image formed just using an alkali. It's snot strictly developer incorporated.
What's being forgotten is that hydroqinone and its derivatives can be and are used as emulsion stabilisers, both Agfa, Kodak and Ilford use these stabilisers and there are books written on the subject as well as Patents and other research papers.
Hydroquinone (and derivatives) are used as anti-odidants in emulsions, they help prevent fog in B&W emulsions and are also used in some colour emulsions. Before WWII both Kodak and Ilford used Pyrogallol in commercial D&P developers alongside Metol & Hydroquinone, becase the Pyro was the stronger anti oxidant it acted as an oxygen scavenger and kept fog levels lower than if it was ommitted.
Eastman Chemical Company sells Hydroquinone (and derivatives) as an inhibitor/stabilioser/antioxidant in Photo grade as well as USP grade.
So Simon Galley is right that MGIV isn't developer incorporated that would require a much greater level, the addition of Hydroquinone or a derivative is ther for other reasons.
I have seen the images in question on that other forum and they are in my opinion more than slight.By no stretch of the imagination would they be acceptable as prints but if you needed to see what was there then you could
I think that we have been dealing with different definitions of "developer incorporated". Rightly or wrongly I had taken Ilford's statement to mean that in practical terms there would be little or nothing to see. My eyes told me otherwise
There's also the problem that many of the hydroquinone derivates that can be used as a stabiliser aren't used as developing agents although they may behave as such.
I agree that the images are more than would be expected if HQ were used as a stabilizer. Sulfite is used as an antioxidant as well, but the most common chemical used is TAI (Tetra Aza Indene) and its derivatives which are not developing agents by any means.
And, in some papers, I have see a full toned image develop with just alkali in spite of the mfgr stating that the papers are not developer incorporated.
Ballasted HQs are used in the interlayer of color materials at the rate of about 10mg/ft sq. This is far from enough of the HQ to develop anything considering that it is ballasted and has a high MW. Its purpose there is to scavenge wandering oxidized color developer and prevent cross layer color contamination.
Kodak used TAI, PMT (Phenyl Mercapto Tetrazole), Methyl Mercuric Iodide and Cadmium Nitrate among other chemicals to both tone and stabilize B&W materials. In addition to those, Agfa used Lead Nitrate, Cupric Chloride and several other organics. After about 1960, Kodak began using all organic salts for toners and stabilizers.
But, many EK papers develop a full B&W image with only alkali.
PS. Most stabilizers are present at about 100 mg per or less mole of silver or about 100 GRAMS. This is certainly not enough to develop any sort of an image.
I have no opinion as to whether the agents are "incorporated developer" or stabilizers in MGIV, but I definitely would call the image developed only in alkali more than "slight". It reaches quite a dark grey. For one of my normal negatives, in a typical 5x7 print, I need about 7 seconds of high contrast exposure to get max black in the rebate. This grey looks about like 4 or 5 seconds gives. This is on photo paper that has been fully exposed to room light.
But there has to be more to this story that I'm missing. I don't know what pH dektol is, but if I was getting the amount of development that I'm seeing with sodium carbonate in my normal split grade printing, it would be hard to judge the high contrast exposure needed -- and it's not. So the paper must not be developing that far only due to the pH of dektol.
BTW, I like MGIV and find it easy to work with. I don't know the correct lingo here, but when I'm judging a print and trying to get the contrast right, it works beautifully. Subjectively, I think the "whites are whiter and the blacks are blacker" and the steps in my test strips separate out beautifully. I'm new at printing and mostly use adorama brand because I'm learning and practicing, but when I use MGIV the process seems to go more easily and I like the results.
I didn't get to my tests this weekend ( a "new" fm2n arrived and I was developing a roll of FP4+ and making prints... which took up what photography time I had! ) but I haven't lost interest. I will add to my list of tests to put a normally exposed print into alkali and see what it looks like. I expect a print that will look flat and underexposed, but fully visible.
An interesting debate, I have spoken to our production people we do not produce any developer incorporated paper emulsion, in relation to a component chemical addition or a 'preservative' that could give a positive test, would you argue with PE ?....lets put it this way, we would not.
Our papers do 'rest' after coating for a period of not less than 7 days before finishing.
Simon ILFORD Photo / HARMAN technology Limited :
I would not expect Ilford to divulge any sort of information about their formula in any situation. I would not if I worked for them! :D
Thanks Simon. Great paper! I used it as my reference for all tests in my book. I have boxes of other types including Kodak, but I used Ilford. Thanks for the wonderful products.
As the 'someone' who "ran some tests on another Forum with MGIV", can I just say that those 'tests' were fairly non-scientific and undertaken purely at the request of another member of the Film & Darkroom User forum who was curious about the apparent conflict between what Ilford had previously stated and what appeared in reality.
Ilford are quite right to say that MGIV is not 'developer incorporated', that description should be reserved for papers like the old Ilfoprint material (of which I must have ordered tens of thousands of sheets in my time!). Some 'modern' papers do have a compound (or compounds) incorporated that will produce a degree of development in the presence of alkali, MGIV is not alone in this, and I would not expect any manufacturer to divulge what it might be.
It's worth adding that the Multigrade IV RC I used for the tests was some years old; how many I can't say exactly, but at least ten. The fact that it still develops perfectly under normal conditions, without any trace of fog or reduction in contrast, is testament to the quality of this product. It was always my paper of choice when working professionally and the stock I have left over is from those days. I now print only on fibre-based papers, so it has languished in a cupboard, at variable room temperature, for all the intervening years. Another testament to the excellence of this paper - long may it continue!
Early Ilfospeed was fully developer incorporated, something Ilford kept very quiet about at the time because they wanted to sell Ilfospeed processors. I used an Ilfoprint machine with Ilfospeed and made my own Activator from Sodium Htdroxide with some Sodium Sulphite and Potassium Bromide added to keep the base fog free and extend the life of the actrivator. I use Hypam 1+4 instead of stabiliser and then the prints went into a second fixer bath before washing. I must have processed many thousands of Ilfospeed prints through my Ilfoprint machine.
When Ilfospeed was updated it was no longer developer incorporated although there was still a weak image like those in your tests Roy.