fotosepp
Hello,
Since I heard that the film doesn’t have the same speed as stated, I’ve now exposed a few rolls at 200 ISO instead of 400 ISO.
Do I need to use different development times now?
Best regards
harv
For me, the HP5 works quite well for black-and-white development at ISO 200 for 11 minutes and 30 seconds in a 1:50 Rodinal solution at 20 degrees: agitate continuously for the first 30 seconds, then tilt the tank once every 30 seconds.
AntiLynd
Hi Sepp,
Whether you need to adjust the development times depends on how happy you are with your results so far. It’s quite possible, for example, that you feel your images are fine in terms of contrast (not too harsh), but that the low exposure means there isn’t enough detail in the shadows. In that case, as an initial test, you wouldn’t adjust the development time much, if at all, but would simply start by exposing more generously.
However: if I remember correctly, you process your HP5 in ID-11 according to the manufacturer’s instructions. So, with an exposure equivalent to ISO 400, in a 1+1 solution for 13 minutes. My guess, purely based on a hunch, would therefore be that your images not only lack shadow detail but also have too much contrast. I would therefore, with an exposure equivalent to ISO 200, reduce the development time by a third, i.e. to 9 minutes. And then see how to proceed from there.
Good luck
Nils
Renate
Hello,
The development time has little effect on shadow detail. Shadow detail is controlled by the speed, and at 200 ISO you’ll get better detail than at 400 ISO.
Highlight detail, on the other hand, is influenced by the development time or concentration. Increased exposure also increases the density of the highlights, and you can adjust this by shortening the development time. However, you should base this on how satisfied you were with the previous results. A shorter development time also automatically results in weaker contrast.
Best regards,
Renate
fotosepp
Hi everyone, thanks in advance!! I’ll get stuck in tonight and have a go at it.
By the way, this is a really great forum! I didn’t think there were still enough people out there interested in analogue.
TR
Another question is how the exposure was set, for example, at 200 ISO. If, for example, you use the built-in light meter of a 35mm camera, which does not yet have an intelligent automatic exposure system such as ‘matrix metering’, and photograph a landscape in portrait format, where perhaps a third of the diffuse sky (the light source itself) is included in the frame, you do not expose for the previously set ISO value (e.g. 200 ISO). In such a scene, you will automatically under expose, resulting in blown-out areas of the image.
I always use generous exposure myself. With cameras that have a built-in light meter, I first point the camera at, say, the ground and then use that reading. This way, I get detail all the way down into the darkest shadows. I don’t change my standard development time. Negative film has an enormous dynamic range, so you rarely need to worry about ‘clipping’ the highlights by developing for a little too long.
fotosepp
In other words, do you set the ASA value indicated on the film, or do you adjust it?
TR
You can’t adjust the value stated on the film, because you can’t change the film’s speed or its chemical composition.
However, I do pay attention to the exposure value that my light meter or camera gives me when it is aimed at a ‘mid-tone (grey) value’ that is in the same light as the actual subject. This is because light meters are calibrated to such a mid-tone value. Only then do I actually have the exact measurement result and can say that I have exposed at such-and-such ASA (namely, at the value set on the light meter or camera).
Extreme example: a small tree in the snow. The tree will be completely underexposed if the camera sees all the white of the snow. It ‘thinks’ it is extremely bright. Yet it is merely very white. I then take the camera, point it at my medium-grey parka, press the exposure lock button and adopt this exposure value. Only in this way will I later capture the detail of the tree trunk on the film.
Had I not done this, I would have exposed a 100 ASA film at approximately 800 ASA, even though the light meter was calibrated to 100 ASA. I would have suffered from severe underexposure and lost all the detail in the shadows.
Later, in a forum, I might have said that I had done the exposure at 100 ISO, as that was the setting on the camera. In fact, as you can see, this would have been a mistake. One might then accuse the film of having insufficient speed, and that is how internet myths arise. This shadow detail is important, by the way, so that the image doesn’t look flat.
If the camera doesn’t have a exposure lock button, you have to do this using the ISO dial. On one of my 35mm cameras, I’ve therefore stuck a ‘button’ onto the ISO dial, which allows you to easily calibrate or correct the light meter:
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So, to come back to your original post, I doubt that you actually achieved the correct exposure for the film as if it were 200 ISO film (even though you had calibrated the light meter to 200 ASA), but rather as if it were 400 or even 800 ISO, provided you were using a camera with a ‘normal’ light meter. Exception: your subjects actually consisted predominantly of elements of medium brightness. For me, that’s rarely the case, if only because of the sky (and I have to correct for it).
