How To Meter Back-lit Translucent Subject?

[arthur_gottschalk]

How should I go about metering a strongly back-lit translucent subject for black and white film? Using my RB67,  I need to include the brightly lit but out of focus background as well as  more dimly lit glass objets  in the foreground. Thanks for your help. 

[Ken Katz]

What type of film?  How will you display the images (printing / web / screen?), how will you process the images (wet darkroom, third party lab, scan negatives and use imaging software?).  I'm not an expert on all this stuff, but it may help getting an answer you can use.

[arthur_gottschalk]

I print in my darkroom and use a third-party lab, Kodak Tri-X. 

[kmac]

I would imagine the translucent object would be metered first up, then meter the other parts of the scene to check for exposure range over the whole scene. If the exposure range is more than two stops, you might need to do some burning and/or dodging.

The general rule for backlit subjects is to open up the aperture one stop to one and a half stops from the average meter reading of the whole scene, but with something translucent, it might be advisable to meter the more "solid" or darker bits of the translucent object and expose for them.

This is my 2cents worth, I'm only going by instinct, I've shot backlit scenes before, but nothing that involved translucent subjects. Experienced members would know more than I do, fortunately.

Edited January 30 by kmac

[AJG]

I would use a spot meter on the translucent objects and pick what Zone you want them to wind up as in your prints. The spot meter could also give you an idea as to how bright the background will be.  Remember that the spot meter will give you a reading to give you middle grey in the print, so if you want the translucent object to be lighter you will have to give it more exposure. 

[Ken Katz]

Its been a few decades since I used Tri-X (or any film), but I would probably meter the darkest area that you would want to see detail and let the latitude of the film take care of the highlight areas.  Obviously, printing will require appropriate dodging and burning in. You may have a dense negative but all the detail should be there.

[James G. Dainis]

I agree with AJG.  Also, use of the Zone system, (expose for the shadows, develop for the highlights) would be of tremendous help.

https://www.jdainis.com/zone.html

[jose_angel]

Backlit scenes are somewhat difficult to control. A few weeks ago I printed a couple images, I was just testing an updated box of 320TXP that I exposed at 200ISO. I was relatively lucky.

Basically, I spot metered the darker areas in the brushes and the surrounding white area of the blind. The separation between them were 5 stop readings so it was a normal contrast scene. I wanted the blind to be almost white with little texture so I developed the negative a bit more to get it brighter (N+1). On the print I found the highlights were right, but the shadows a bit soft, so I had to print it with a grade 3 filter. This is how it looks (straight unedited scan):

 

[jose_angel]

I did a second shot, with little changes. Same spot metering over the darker brush sticks (III) and over the highlighted brush hair (VIII) All the other areas were in between. I gave a normal development and the print got perfect with a grade ·2 filter. I was so lucky. (Again, straight print scan. No dodging or burning in both images):

Development time should be specific for a given scene contrast in order to get an easy to print negative. If not, too much work under the enlarger is deserved.

Edited February 3 by jose_angel

[Rick Helmke]

This is easier than it looks. Meter for the background and use a flash or other light source to expose the shadow area to within a half stop of the background. Fill flash basically, should be simple enough with an RB. A flash meter would be helpful but something like a Vivitar 283/285 will do. Just set it to expose the fill area about 1/2 stop less than the backlight ie if the background is metering at f/11 then set the fill flash to expose at f/8 or just a title more. Gives the whole thing a more natural look.

 

Rick H.

[AJG]

11 hours ago, Rick Helmke said:

This is easier than it looks. Meter for the background and use a flash or other light source to expose the shadow area to within a half stop of the background. Fill flash basically, should be simple enough with an RB. A flash meter would be helpful but something like a Vivitar 283/285 will do. Just set it to expose the fill area about 1/2 stop less than the backlight ie if the background is metering at f/11 then set the fill flash to expose at f/8 or just a title more. Gives the whole thing a more natural look.

 

Rick H.

Fill flash could be a good way to shoot this, but the OP did mention that his subject was translucent, which could be a problem if the level of flash lighting isn't carefully controlled.  And fill flash could have caused some problems with the images that Jose Angel shared--glare on the window behind the brushes could have been distracting and a big problem to deal with in a conventional darkroom print. 

[arthur_gottschalk]

Thanks all, very helpful. 

 

[rodeo_joe1]

Old film-shooting adage: "Expose for the shadows and let the highlights take care of themselves." 

WRT spot metering - this assumes 1) you have a spotmeter, 2) the spotmeter has a narrow enough angle and is baffled well enough to cope accurately with shadows adjacent to bright highlights - not many are - 3) you know what you want as a mid-tone, and 4) the film can cope with both highlights and shadows. If it can, then there's little point in spot metering at all and an average reflective or incident metering is all that's needed.

Another consideration is the 'flare factor' of lens and camera. With the setup shown, which has a large area of highlight compared to shadow, the shadows will automatically get 'filled' simply from camera body flare and internal lens reflections bouncing light about. Especially if it's an old single or non-coated lens. 

[James G. Dainis]

I took this shot long ago  using a Sony Mavica FD73 digital camera. The purpose was to show eBay users how to back light a translucent item very simply.  It is just a straight photo with the lighting supplied by a desk spot lamp shining on a light background.  No real magic needed.

[arthur_gottschalk]

Very nice. But is the light shining directly on the subject or is it traveling toward the camera through the backdrop? That would be my situation. 

[James G. Dainis]

In my above photo of  the swan the light is traveling toward the camera off  the backdrop. there is no front lighting except dim ambient.  I think all photos of glassware looks best with the light traveling through the glass.

[AJG]

My wife, an award winning glass artist would disagree--one light from above the camera position with a 20 ° honeycomb.

[James G. Dainis]

AJG, that doesn't look  translucent to me.  It doesn't even look like glass.

[jose_angel]

Very nice art on glass. Yes, it is translucent in some parts (check the stems, especially on the grapes), others look opaque.

As James points out, maybe it doesn't quite show his true character. I would try to highlight the translucency and its fragile nature... but please, don't ask me how! 🤔

Edited February 28 by jose_angel

[AJG]

4 hours ago, James G. Dainis said:

AJG, that doesn't look  translucent to me.  It doesn't even look like glass.

Trust me, the fruit is all glass.  The stem on the grapes is translucent as are the stems on the pear and the apple. The bodies of the fruit start out as clear borosilicate glass tubing before being cased with colored glass (both rods and powdered glass frit). This happens over a 3000° propane-oxygen flame.  Since the artist's goal is the utmost in realism within the possibilities of the glass medium, the lighting that I do is intended to enhance that realism.  My wife had used other photographers before we met and was frequently frustrated with their results since most of them started out wanting to backlight her work to avoid glare. 

[Bettendorf]

5 hours ago, AJG said:

Trust me, the fruit is all glass….

Very well put AJG.  l’m sure that ends that discussion.

I think both the glass and photo art are primo.  Kudos to you and your wife. 

[AJG]

2 hours ago, Bettendorf said:

Very well put AJG.  l’m sure that ends that discussion.

I think both the glass and photo art are primo.  Kudos to you and your wife. 

Thanks for the kind words...  It is difficult to shoot her work, but it is good enough to be worth the effort.