Black point/white point in capture nx

Hi Folks,

Hoping someone can help me. I have D300 and capture nx and am hoping to sell some of my pics to stock.

I notice alot of sites say something like "we do not want to see highlights blown out, or your shadows filling in (RGB in photoshop should be limited to a white point of less than 248 and a black point no darker than 4- I presume this means 4 or less).

Could someone explain how I find out the current black and white point values for each photo once I have opened the file. I can see the histogram on the screen and and a graph with values from 0-255, but I don't know how I find out what the images current black and white points are. They may be ok.

All information much appreciated.

Regards

Chris

An amendment - I think I should have said 4 and above for a black point no darker than 4? Not too sure

Chris

Perhaps it is not possible to find current black point/white point values for an image?

Hope someone can help

In Capture NX, you can set the histogram slider for double threshold. Then drag the left (black) point in, and the right point in. This will show you where your dark and light areas are.

Then go to levels and curves. Using the black or white eyedroppers, you can move to one of the highlighted areas and see the values displayed under the histogram.

Thanks for replying, I'm just going to try that now.

Chris