Is 18% Grey 18% Grey?

Hi, I like to shoot in RAW and manual mode so use a hand held meter.
I have looked on-line to try to find out if there is difference between for example The X-Rite 18% Mini ColorChecker Grey Balance Card,
The LASTOLITE 18% EZY-BALANCE GRAY CARD or any of the other 18% grey cards on offer. Understand the quality of the material used may be some what suspect in the very cheap cards but is the 18% grey quality actually the same in the better known branded 18% cards?
Thanks
Russ
I have looked on-line to try to find out if there is difference between for example The X-Rite 18% Mini ColorChecker Grey Balance Card,
The LASTOLITE 18% EZY-BALANCE GRAY CARD or any of the other 18% grey cards on offer. Understand the quality of the material used may be some what suspect in the very cheap cards but is the 18% grey quality actually the same in the better known branded 18% cards?
Thanks
Russ
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No Russ, they're not all equal. It's all about the quality of the surface and whether or not it's able to reflect a perfect RGB balance of grey. But somehow I doubt this has fantastic real-world effect - most apparently neutral surfaces seem to be adequate for snapping mid-tone colour into place at least. Depends on how accurate you need to be, I guess.

Quote:Why bother with white balance in RAW that much? RAW allows to adjust it to whatever you may need later.
Aye, but if you shoot a subject with no neutral reference you're stuffed if you want to later easily correct the colour.
Did you mean keeping that particular frame with the grey card in it as a reference? If yes - I am with you, it truly simplifies colour adjustments during RAW processing (even with WB set to AUTO when shooting).

Otherwise, it only affects the small JPG preview incorporated in RAW file and the initial image render in RAW processing software - if EXIF was taken into account.

Quote:Did you mean keeping that particular frame with the grey card in it as a reference?
Yes, that's exactly what I meant. In many instances outdoors a colour cast is effectively the reason for taking the picture, so nobody wants to always nuke everything with heavyweight white balance corrections, but a grey card is a useful thing to carry (I guess the world's minimalists will argue against). When I don't have one I do sometimes make an attempt at getting the raw JPEG right, just to remind myself vaguely what the colour looked like.
I have cheap and less cheap grey cards lying around - maybe I'll conduct a geeky experiment at some point to see if any difference can be discerned. Generally I use any of them just to get the colour in the right ballpark.

The 18% refers to the reflectivity of the grey on a scale where black is 0 and white is 100. (18% is halfway between - which puzzles some folk).
But, on that basis, I would imagine that the kind of surface the card has and, indeed, the materials used in the manufacture of the card, would have some effect on the reflectivity.
But, on that basis, I would imagine that the kind of surface the card has and, indeed, the materials used in the manufacture of the card, would have some effect on the reflectivity.

A 18% Grey Card , to the best of my knowledge, is used for both exposure and whitebalance.