How can I make a 18% gray card in PS? I need one in order to adjust the pictures to the right white balance in post processing. I know how to do the black and white part but I not shure about the gray . Any help appreciated.
I believe it is 128, 128, 128. Correct me if I am wrong but creating one in photoshop is going to be of no use. The whole point is it physically being in the scene so you can then measure your values from it.
You basically would just be creating the perfect grey card that has no connection whatsoever with the images colour cast.
The back of many books include a Black/Gray/white card (Kelby's books)
Also note that the gray card for digital on all these cards are much lighter gray that the standard film gray card... also Dave Cross , one of Kelby's on the road teachers suggest 133/133/133 Sooo... dive in and guess at what is correct??
The three color card still works the best ...
Don
Borrow a friends gray card to do this, from a book by Bryan Peterson!
You'll need to calibrate your palm, first. To calibrate your palm, take your camera and grey card into full sun, and set your aperture to f/8. While filling the frame with the Grey Card, adjust your shutter speed until a correct exposure is indicated.
Now, hold the palm of your hand out in front of you. The camera's meter should indicate that you're about +2/3 to 1 stop overexposed. Make a note of this.
Then, take the grey card into open shade, and again meter your camera's aperture at f8 and again adjust the shutter speed to show correct exposure. Again, meter off of your hand, and you should again see that the exposure is +2/3 to +1 stop overexposed from the reading off of the grey card, the same as it was in sunlight.
So, you now know that taking a reading from the palm of your hand gives you (either) a +2/3 or +1 overexposure.
Next time you're not sure about your exposure settting, you can use the palm of your hand to get an accurate reading (by adjusting accordingly)
Looks a bit complicated but it never fails.
This thing is worth it's weight in gold. I was using a grey card in an arena and it did no good. One shot with the ExpoDisc and my white-balance problems went away.
jkittmer wrote:
I believe it is 128, 128, 128. Correct me if I am wrong but creating one in photoshop is going to be of no use. The whole point is it physically being in the scene so you can then measure your values from it.
You basically would just be creating the perfect grey card that has no connection whatsoever with the images colour cast.
bourbonnais wrote:
Yes my bad -
It is 128, 128, 128
Sorry,
Robin
I've always wondered about this. Why is 128 across the RGB 18%? Wouldn't that be 50% I know it would have to do with all the physics and inverse square and alignment of the planets.
Kenji your are not wrong.. you are Right...:+}
Kodaks 18% is or was for exposure not white balance....
You actually want a lighter grey for Whitebalance..
Snook
The WhiBal card gives me perfect balance every time. I bought the 8.5x11" and cut off a pocket size section (that included one the contrast stickers) so I have both studio and field size.
. Any help appreciated.