Film users... need your advice

[edfck]

interesting read, student :thumbsup:

i have some queries that crop up. suppose if the film loaded is a ISO100 film and somehow or rather, i've set the cam to shoot at ISO200 or higher, and that is likely to result in underexposures.

(1) if i had realized the wrong ISO settings used and tell it to the shop before developing, what are the countermeasures that they'll do to restore back to proper exposure of the negatives?


(2) if i did not tell them about this wrong ISO settings and they just process under default settings, the negatives will look underexposed. is there still any remedy (such as lengthening the exposure time) that when printed on paper, it'll still look as a properly exposed?

1) Student has answered yr question with lots of technicality. In short, its known as push processing.

2) er... it depends on how much underexposed. in B & W, i managed to print with 2 stops either over or underexposed but image turn out flat, as in low contrast. 1 stop difference not so bad. as for color, very small margin. 1 shop difference n the pic's flat. with some adjustments, it can still look properly exposed but image quality will definately drop.

 

[lsisaxon]

Student, would like to seek some clearifications from you. By extending development. Am i right to say that it is push processing? I got this conclusion from those B&W developing time charts. By developing at a higher EI, you have to develop the same film longer only.

You said that the the high values will be developed more and the shadows remains unaffected. I am abit confused here. When can you actually shift the zones by 1 stop forward? Instead of expanding the zones which you have described earlier. Hope you can help to clear my doubts.

You can think of it this way, when the silver halides are exposed to light, there will be a chemical change which will cause the silver salt to become silver during development, thus becoming opaque. So the more you develop, the more salt becomes opaque silver.

When you have underexposed the film, since you did not give the silver halides enough time to react, you will need to develop more to get back the silver. However, the sensitivity will be different and you will get a higher contrast negative.

If you have not told the lab to "push process", then you will get a "thin" negative and when you print, you will need to expose less (it's negative, white becomes black, black becomes white), not more. But the effect you will get will be a loss of contrast and dynamic range. Grains will become more prominent because they are sparse, especially in colour where the grain sizes are bigger.

 

[Snoweagle]

Usually the larger u print with a higher ISO grade film, the grains will be more prominent.

 

[boen]

In addition, at lower ISO film ratings a tripod is suitable to prevent motion blur. For me i always use an ASA 400 speed film for all rounder shots...works day and night!

what does ASA means? is it a brand? sorry ah.. me still new.. heh. Kodak max400.. so far the colour i find they are ok.. just the grainy part i dun like.. heh.

 

[student]

Student, would like to seek some clearifications from you. By extending development. Am i right to say that it is push processing? I got this conclusion from those B&W developing time charts. By developing at a higher EI, you have to develop the same film longer only.

You said that the the high values will be developed more and the shadows remains unaffected. I am abit confused here. When can you actually shift the zones by 1 stop forward? Instead of expanding the zones which you have described earlier. Hope you can help to clear my doubts.

My apologies for not answering earlier.

Isisaxon has given some explanation, but not quite accurate.

When one increases development, either by increasing time, increasing concentration of developer, increasing temperature, and increasing agitation, one will push the zones to a higher level. The amount of "pushing", and hence the target "zones" depends on how much one changes the variables.

Isisaxon is right up to this point. However, if one has severely underexposed a negative, there is very little that one can do to bring the shadows up. You just cannot create something which was not there. If the exposure is inadequate, the shadows are not exposed at all, and no amount of development tricks can salvage it. That is why Ansel Adams said "expose for the shadows".

There is also another point. There is a difference in the way nagatives to push processing. The higher zones are somehow more sensitive to push processing than the shadows. And this increases the contrast.

But if one REALLY wants to increase the contrast severely, then the approach is NOT to underexpose and overdevelop, but to OVEREXPOSE and OVERDEVELOP.

 

[Snoweagle]

what does ASA means? is it a brand? sorry ah.. me still new.. heh. Kodak max400.. so far the colour i find they are ok.. just the grainy part i dun like.. heh.

ASA stands for 'American Standards Association'. We normally use ISO (International Standards Organisation) cos it's the most common, similar to ISO 9000, 9001, 14000, etc.

Film colours are the best i must say. As long as you use higher film speeds but don't print large, the grains will not be so obvious.

 

[lsisaxon]

My apologies for not answering earlier.

Isisaxon has given some explanation, but not quite accurate.

When one increases development, either by increasing time, increasing concentration of developer, increasing temperature, and increasing agitation, one will push the zones to a higher level. The amount of "pushing", and hence the target "zones" depends on how much one changes the variables.

Isisaxon is right up to this point. However, if one has severely underexposed a negative, there is very little that one can do to bring the shadows up. You just cannot create something which was not there. If the exposure is inadequate, the shadows are not exposed at all, and no amount of development tricks can salvage it. That is why Ansel Adams said "expose for the shadows".

There is also another point. There is a difference in the way nagatives to push processing. The higher zones are somehow more sensitive to push processing than the shadows. And this increases the contrast.

But if one REALLY wants to increase the contrast severely, then the approach is NOT to underexpose and overdevelop, but to OVEREXPOSE and OVERDEVELOP.

Yes. There is a whole lot more to learn in film photography if you do processing yourself. That's why in a sense, it is more tolerant to slight overexposure than underexposure when shooting negatives.

 

[lsisaxon]

ASA stands for 'American Standards Association'. We normally use ISO (International Standards Organisation) cos it's the most common, similar to ISO 9000, 9001, 14000, etc.

Film colours are the best i must say. As long as you use higher film speeds but don't print large, the grains will not be so obvious.

Film ratings started with ASA. The Germans has their own DIN standard. ASA 100 is equivalent to DIN 21. ISO actually combines both to give something like ISO 100/21°. So when we rate the ASA number without the DIN number, it is just the ASA number we are quoting, not the ISO. See how much powerful the Americans are compared to Europeans?

ASA-American Standards Association
DIN-Deutsches Institut für Normung
ISO-International Standards Organization

 

[Snoweagle]

Film ratings started with ASA. The Germans has their own DIN standard. ASA 100 is equivalent to DIN 21. ISO actually combines both to give something like ISO 100/21°. So when we rate the ASA number without the DIN number, it is just the ASA number we are quoting, not the ISO. See how much powerful the Americans are compared to Europeans?

ASA-American Standards Association
DIN-Deutsches Institut für Normung
ISO-International Standards Organization

Yup u're right! Here's an interesting site on ASA, DIN and ISO.

http://www.minoxlab.com/Don_Krehbiel/mpl/dkasa.htm

 

[boen]

wow, so any films u guys "die die" will recommend one? TMAX is for black n white right?:sweat:

 

[student]

wow, so any films u guys "die die" will recommend one? TMAX is for black n white right?:sweat:

TMax is for black & white.

But I would not recommend it to you.

At this stage of your adventure of film B&W, stick to Kodak TriX or Ilford HP5. These films are much more tolerant to exposures inadequacy and bad development techniques.

 

[boen]

TMax is for black & white.

But I would not recommend it to you.

At this stage of your adventure of film B&W, stick to Kodak TriX or Ilford HP5. These films are much more tolerant to exposures inadequacy and bad development techniques.

okok.. thanks for ur advice!:bsmilie: