Overexposure at capture or scan?

[GenghisWayne]

Sorry, I'm new to film so I have basic questions.

I've just had a roll of BW400CN developed and scanned at the local shop. The scans look overexposed to me. My question is it something I did at exposure time or could it be that the scanner did this and my negatives are better than what the scans are showing?

I rated the film at 400 and more or less used what the camera's meter was telling me (Canonet QL17). The camera is new to me but it's possible that it has problems (although I'm assuming it's the photographer at this point, not the equipment ).

I just want to know if I should adjust (rate the film 600-800) or if I should have some prints developed and see if there is a difference from the scans?

Thanks in advance,
-Wayne

 

[coelacanth]

Hi.

Usually, with negative films (b/w and color), you can save over exposed shots much more easily compared with digital or slide film (dig/slides are opposite).

BTW, the film you used is basically "desaturated color film" which turns to be monochrome tone, but uses C-41 process (same as negative color films) to develop.

But first of all, you can't really trust scanned images especially from a shop that you are not familiar with. Try to see if you can find any details left in the negative. A lightbox or a bright computer display with white screen shown, and a magnifier will help. Because it's tiny, you might have hard time seeing any details left in the blown out area, but I bet you'll be amazed how well these negative films preserve the details in bright area once you scan the film right.

 

[coelacanth]

As for the Canonet QL17, although I'm not familiar with the model myself, a google search told me it uses 1.35v battery which is no longer available in the US and many other countries.

If you are using 1.5v battery, the metering will be incorrect. You can get an adapter for the battery so you can use regularly available 1.5v battery, or compensate the difference by telling camera "wrong" ISO. Well, third option is to modify the camera circuit to adapt 1.5v battery "natively" but you probably don't want to do it yourself so there is a cost.

 

[degruyl]

What he said. I suspect the scan exposure was set to high.

I have never heard of negatives being exposed at greater than the box speed for normal development. It is fairly common to derate the speed of (C-41) films by 1/3 or 2/3 or even 1 stop.

The issue, of course, is whether your camera has a good meter with a good voltage battery in it. Can you check some meter readings against another camera or against a hand held meter?

(Out of curiosity, does C-41 "B&W" have an orange backing? I have never used it.)

 

[mackigator]

Hmmm. Try comparing against another digital camera set to center weighted.

Also try shooting a test roll in a controlled environment with some easy lighting. I don't have a Canonet, but I could see how a meter might average that high contrast scene and mess up if it were off by a stop.

 

[Dwig]

It should also be noted that the QL17 and any other similar leaf shuttered cameras with 1/500th max shutter speed and a minimum f/stop of f/16 can't properly expose any film higher than ISO 200 in full sun. Even with a perfectly accurate shutter and perfectly accurate meter you will get about 1 stop overexposure with an ISO 400 film.

Full sun with an ISO 400 film requires only a 1/400 sec at f/16. The problem comes from the fact that a leaf shutter opens from the center outward and closes from the outer edge toward the center. The real shutter speed at f/16 is a bit longer than at f/1.7. The difference with small modern shutters is about 1 stop. Some old large leaf shutters on view camera lenses can be as much as 2 stops slower at minimum aperture than at maximum.

 

[GenghisWayne]

As for the Canonet QL17, although I'm not familiar with the model myself, a google search told me it uses 1.35v battery which is no longer available in the US and many other countries.

If you are using 1.5v battery, the metering will be incorrect.

Good point, but I forgot to mention that I bought a zinc-air, 1.35V battery which is supposed to be a replacement for the old mercury battery. I think we can rule this out as a problem.

Out of curiosity, does C-41 "B&W" have an orange backing? I have never used it.

Well, like I said, I'm new to film, but the negatives look to be made of the same film backing as my color negatives. Hope that helps.

It sounds like it could be either problem: scan gain too high or the exposure is wrong. I'll test against another camera's meter.

Also having a few prints made might show detail in the blown out areas pointing to a scanning problem, right? Over-exposed prints wouldn't necessarily mean the negatives were the cause though, right?

One thought on the possibility of a scanning "too brightly": could this be a common error if the operator were used to scanning color negative film?

Thanks again for everyone's help.
-Wayne

 

[oftheherd]

It should also be noted that the QL17 and any other similar leaf shuttered cameras with 1/500th max shutter speed and a minimum f/stop of f/16 can't properly expose any film higher than ISO 200 in full sun. Even with a perfectly accurate shutter and perfectly accurate meter you will get about 1 stop overexposure with an ISO 400 film.

Full sun with an ISO 400 film requires only a 1/400 sec at f/16. The problem comes from the fact that a leaf shutter opens from the center outward and closes from the outer edge toward the center. The real shutter speed at f/16 is a bit longer than at f/1.7. The difference with small modern shutters is about 1 stop. Some old large leaf shutters on view camera lenses can be as much as 2 stops slower at minimum aperture than at maximum.

I think I remember reading that some shutters exposed for a little less since the shutter was only open for 1/500th second. But not enough to get even one stop outside most film's latitude. And the old shutters were designed to take that into consideration. They were designed to begin letting in light along the entire length of the shutter blades. Some cheaper P&S shutters did not do that. I don't have my QL17 III handy to see if they have that type of shutter or not. I can tell you that I get good exposures from it as long as I use a 1.35 volt zinc battery in it.

 

[Dwig]

I think I remember reading that some shutters exposed for a little less since the shutter was only open for 1/500th second. But not enough to get even one stop outside most film's latitude. And the old shutters were designed to take that into consideration. They were designed to begin letting in light along the entire length of the shutter blades. Some cheaper P&S shutters did not do that. I don't have my QL17 III handy to see if they have that type of shutter or not. I can tell you that I get good exposures from it as long as I use a 1.35 volt zinc battery in it.

The compensation trick is only partially effective. It helps at middle apertures, but does little for extremely small apertures (f/16). There is no way that "shutter" can taken this problem "into consideration" in systems with independent sets of shutter blades and iris blades. Meters can be setup to make a compensation, but in this case there is no room to compensate. Proper exposure with ISO 400 in full sun requires the highest shutter speed and smallest aperture available on a QL17 leaving no room for compensation.

It was only the full automatic models that integrated the shutter and iris functions into a single set of blades that could effectively compensate. These had the advantage of never using the top shutter speed with anything other than the smallest aperture.

 

[not_in_good_order]

In my experience, whenever I had a lab scan my film, the files came out overly bright with the highlights blown out. It is one of reasons I bought my Nikon Coolscan 5000.