Older Film Developing Times, Compared To New ?

[russel_grainger]

<p>Today I bought a very old roll of Ilford Hp5 the expiry date on the film box was 1989, after opening it and reading the info sheet inside I found it interested that Ilford gave to different times for normal contrast and high contrast. <br>

The high contrast time for this roll of hp5 in 1d-11 1:3 is 22mins for normal contrast and 30mins for high contrast.<br>

I looked this modern combo up on my digital truth app on my iphone and it gives a time of 20mins, whats makes the modern version of this film different to the old one as the starting point time is 2 mins less than the old time for a normal contrast neg.</p>

<p>Also will this film still be ok to use ? it was in the box and in great condition, I only put it in my Brownie "E" as its not worth using it on anything serious.</p>

[chris_waller]

<p>It all depends on how it has been stored but in any event after 24 years it will have lost a good 2 stops of speed and fog will be high. All that considered, development times as given on the box are out of the window. Rate it at 100 ASA and dev in ID11, 1+1 for 15 minutes.</p>

[Alan Marcus]

<p>Films are made by mixing the ingredients in giant kettles. Each batch will have unique properties. Every attempt is made to insure their will be consistency batch-to-batch. As time passes the uniformity of the constituent ingredients will change. A key component is gelatin derived from animal bones and hides. Gelatin varies as to its chemical composition based on the diet fed to the animals. Thus over time, the recipe used to make the film undergoes changes.<br>

In addition, a two minute variation in 20 minutes is a 10% change. Such a small change in developing time is unlikely to produce a conspicuous difference. </p>

[steve_mareno1]

<p>The emulsion probably changed during those 24 years, which is why the times changed. I agree, the film is probably going to be fogged no matter what, but you might be able to get some scans from it. Printing it on an enlarger would probably be not possible.</p>

[russel_grainger]

<p>Thanks for the response guys, I understand the film will be pretty bad hence the reason i just through it in a box brownie for a few random shots and if anything is to turn out it will be a bonus. <br>

I was just curious to as why film companies do not give this base info for normal contrast or high contrast anymore.<br>

I sometimes go for a longer development for a bit more contrast but I didnt know that you could go that much onger on dev times, 8 mins just seemed crazy to me and I would of thought you'd of got a neg which was rendered useless.</p>

[tklim]

<p>Indeed, years ago Ilford were consistent in giving two development times for their films, G=0.55 (mean gradient) for a condenser enlarger and 0.70 for the so-called 'cold cathode' enlarger. Incidentally, negatives intended for scanning should ideally be less contrasty, just like those for a condenser enlarger or even less... Currently I have established my development processes to yield negatives corresponding to G=48...</p>

<p>In the particular case you describe I think I'd go for a low-fog developer or add some benzotriazole (0.2 g / litre) to any commercially available brew. Unfortunately - you don't have that much of the stuff (film) to allow an extended testing procedure. Russian roulette, then... ;) <br>

Anyway - as you said yourself, any usable image on the neg will be a bonus, your best choice would be to follow Chris Waller's advice, imho. </p>

[glen_h]

<p>I have developed Verichrome Pan with pictures I took 40 years ago, and which I didn't especially try to keep cool. Tri-X and T-max 400 have a noticeable fog after 30 years or so, again not kept especially cool.<br>

<br />HP5 may be closer to Tri-X, so I would expect some fogging, but good enough for a Brownie, exposed at EI 100 or so. To me, the reduced EI is not because it is less sensitive, but to get above the fog level.</p>