I use the thumb rule that says caucasian skin, placed at around zone 6, usually gives the "correct" exposure and pleasing tones.
This means, if you take an incident reading, set a camera with a spot meter to this exposure and then meter a middle tone in the caucasian face, the spot reading will usually suggest that this reading is 1 stop over "the middle notch" in you camera.
By taking an incident reading, you are establishing an exposure that will place 18% gray in zone V (middle gray in the middle). When you do this, caucasian skin which is thought to be one stop brighter, will be placed at zone VI and thus your exposure will render skin naturally.
I've found this to work very well in natural light portraits, especially outside when there is overcast weather.
Off course you can be anal about it and state that makeup, light hardness and direction will alter the highlights in the skin for example, but if you have nothing else, make an incident reading and shoot.
(Incident readings should be measured from your subject, in direction of your camera)
My two € cents...
All photographers will have their individual methods in portraiture, and it never hurt to experiment.
Incident: cheek in shade; cheek in shadow, front of face, add mid-tone (or grey card), average all — none of these specifically with aim-back (cone to camera).
If using mono film, meter should read in 0.5 to 1 stop increments. With tranny film (unlikely in this scenario), meter to 0.3 steps. You have a lot of latitude in mono and small adjustments generally will not have a lot of effect as opposed to printing versatility in the darkroom.
Spot metering will give any number of variations depending on what you are specifically aiming at, and 5° is too great an angle for spot.
I tend to like reflected spot readings off of the brightest parts of the skin and placing them at zone VII while using a developer and film combo that doesn't block up highlights.
Or else I put my important shadows at zone IV and then develop by inspection, pulling the films when my highlights look "right" to me.
I note that both methods tend to give an extra stop of exposure vs "standards". This is my preference and I know I'm not the only photog who likes to give portraits more light than landscapes.
There is no correct method. Use what works for you, ultimately this will be a part of your look.
So Saturday I hand-loaded some fresh Delta 400, not exactly the OP's Tri-X, but close in a general sense.
Ran a test to find my limits again, developed using DD-X by the book for EI 500, metered using the "duplexed incident" method at EI 500. Normal incident reading was within 1/3 stop.
Shot 10 consecutive shots inside about 10 seconds: portrait of a black, white, and brown dog in northern window light; so normal studio portrait contrast.
Shot at EI's 125,160,200,250,320,400,500,640,800,1000. The frames at 125 & 1000 were lost because of cutting errors when I cut the roll to develop and test other EI's from the same roll separately.
Each print from 160-800 was printed to get "the same print". Given the results even if 125 & 1000 had a taste of clipping the prints would have been just fine.
The prints from 160 & 800 are virtually indistinguishable. At arms length I can't tell the difference. With a 10x loupe I can barely tell in the near white and near black areas, in the mid-tones I can't tell them apart at all.
My point here is that the OP's Tri-X, like my Delta 400, has really good latitude.
Get either of these films "somewhere in the ballpark" and you have a really high probability of getting the print that is expected.
I've never shot Delta, but plenty of Plus-X, Super-XX, Bergger 200, and a bit of Tri-X... they all share that wonderful characteristic. That is exactly why I generally take a quick incident reading and don't worry about spot measurements or "duplex incident" techniques. It is very interesting to hear the results of a real experiment!
Originally Posted by markbarendt
p.s. I'll bet you'd get the same result using a 30 deg. reflected lightmeter reading too. :laugh:
I like using the duplexed reading to set the camera for the general lighting situation, not necessarily each shot; this gets me reliably inside the limits.
After that I typically meter and reset the camera again only when the lighting situation changes significantly.
I should look into the mechanics of duplexed incident metering -- the closest thing to that practiced by me would be measuring twice becuase I can be insecure about taking only one measure. :)
Like you, I'll measure once or twice in a shooting session. Last week I shot four hours and metered twice: once in bright light and again when the cloud rolled in. That was enough light information for the entire day. The EVs were 15 and 13... which may not have even been enough to make changing the shutter worthwhile.
Dunn & Wakefield Exposure Manual, 3rd or 4th edition.
Thanks, Mark. I thought Dunn had something to do with that!