Setting levels

[Ken Lee]

You can include a little portion of the film edge, and adjust the left-hand slider to clip it at Zone 0.

However, do not always place the right-hand slider at the right end of the curve. Not all subjects contain pure white values. Below is a recent example.

Perhaps my statements have been unclear. I follow the same approach as cinematographers: start with the subject itself. When perfectly lit, exposure is effortless, and so are developing and printing: resulting images have a natural analog quality. If we can't control the subject, then the next best thing is exposure and development. If we can't get ideal exposure and development, we can correct it while scanning or in the darkroom. If we can't get the scan right, then we can correct it in Photoshop. The ideal is to make corrections as far upstream as possible.

Ansel summarized this approach far more concisely: "When asked what camera I use, I reply 'The heaviest one I can carry'."

Massachusetts 2010
Kodak 2D, 450mm Fujinon C
5x7 HP5+, Pyrocat HD

[Greg Miller]

1 - I'm really trying to understand why you limit the input value on the highlights, as Greg was asking about. The way I'm thinking about it is that if your highlights appear to safe to cut off at, let's say, 230 and you leave it open to 255 - sure, you're going to have no detail above 230 to work with (and your densitometer readings would show that). I guess the reason why I have been leaning towards scanning "wide open" (to 255) is that those densitomer readings and histogram are based on the quick preview scan. I don't know exactly how accurate that preview is, but I like to err on the side of assuming that there may be a little more detail on the fringes of the histogram than it captured in the preview. If you cut the input off too low, it's possible to clip those details in the final scan. My preference is to scan the full input range and then open it up in Photoshop with a levels adjustment (well, I use curves to achieve it, but "levels" is a more obvious idea) watching for what areas are actually going to clip first. (In this case of course clipping could be at the maximum 255, or at a lower output value as you suggest, which I totally understand).

Note that Jim is not setting the "input" value for highlights to 250, he is setting the "output" value for highlights to 250. So he is not clipping highlights. An input value of 255 would be mapped to 250 (and all values below 255 would be remapped as well).

There is no right or wrong here. My preference is to do this step in Photoshop when preparing an image for output. That is because different output media (monitor, matte paper, glossy paper) have different characteristics and capabilities, and those characteristics will change (usually for the better) over time. I prefer to leave the output value at 255 so that I can keep brighter whites for preparing an image for my website and set a different value when printing on different papers, and also maintain the maximum amount of information for if/when the output media improve for the better.

Of course this only matters for images that have information greater than 250.

I also change the output for blacks during printing (not during scanning). I have printed a step wedge for each of my paper/ink combinations to find the lowest value of black that I can print and still hold detail. For example, with my Epson 4800 and Hahnemuhle German Etching paper, any value below 9 will render as the same value of black (and therefore will not have detail between 0 and 9). So during printing I set the black output value at 9 if (and only if) the image contains black values below 9.

[bob carnie]

I like Jims explanation, everyone has a different method for sure.

One little tip that I like to do is activate the digital Colour Meter . app in all my Macs
I set the eyedropper to minimum and use the lab setting.. If you are more comfortable with RGB numbers then set it there, or if you are more comfortable with CMYK settings then set it there.

To Jims point , I will set the density in the high and low end to points that I know will create tone in significant detail areas that I want to print.
I must say that usually I move the sliders out side the clipping areas to leave as much detail but I use the meter to make sure I have the density readings for paper I am going to print.

This meter is used all the time to verify colour and I will wave it over any and all areas of images , just to practice my eye to see and understand colours/density using the digital meter. I find it to be a wonderful little tool to use to help look for colour inbalances when scanning negs as well.

I do not know if this app. is available for PC.
I wish someone could adapt this device to read original scenes.

[jim kitchen]

Folks,

I would like to take a brief moment to clarify a comment I made earlier about tweaking the scanner's upper input value to make sure that it does not breach the output value that I set within a scan. I will use Barry's example again…

I mentioned that I peg the scanner's output value to 250 for reasons stated earlier, but I also mentioned in passing that I adjust the upper input value to verify that the scanner's upper output value does not surpass 250, while using the densitometer tool. For example, I locate a few pixels or a larger pixel grouping that I know I want to control in the finished scan, and where I do not want any of the pixels in that grouping to migrate past 250. I locate that grouping by scouring the pre-scan within areas that are logically bright and look bright, such as a cloud formation, a hand and, or a bright forehead in a portrait.

Upon locating that grouping, I discover that if I left my setting at "222" and, or at position "a" as illustrated within Barry's example, I might see that the illustrated values in the densitometer window are red in colour when they are greater than 250. This is a clear signal that my current upper input limit at "222" is a wee bit too robust, and I must adjust my upper input limit to a higher value, which happens to be in the direction of position "b," therefore making the red density values disappear, and therefore making the entire scanned image darker by two, three, or four density points. I do believe that the densitometer software is intelligent enough to warn you that your upper input limit setting requires further adjustment because a few pixels exist that will be clipped. I do notice that the clipped values are present in the scanned file, when I do not adjust the upper input limit properly. This upper input limit tweak would surely be at the discretion of the author regarding whether the adjustment is required or not and, or whether the adjustment adds value to their scanned image. Sometimes we become too technical, but sometimes being too technical adds value.

Anyway, I thought I should include this minor fact to allow you to explore the software a bit more thoroughly…


jim k

[MumbleyJoe]

Thanks for all of the clarifying points (Jim and others) - I think I'm more on the same page with you than it may have initially appeared. It is, indeed, a bit of a black art and certainly don't think there's a single approach to fit everyone's needs - if there was, I would kindly ask that someone tell me those precise settings

To date, my general approach has been to limit my output to the ~10-245 range, but generally keep the input range at its fullest. This may not give me the best looking scan, but gives me a good working file to take into Photoshop where I'm much more comfortable adjusting the levels to where I think they ultimately belong. I find those adjustments in Photoshop trivial, but have not been nearly as comfortable trying to set those values in the scanning software itself (though I have not really played with the densitometer yet) - so I am conservative with my scanner settings.

Thanks again - I'll probably read through everything yet again along with the example and see if anything still trips me up. The bottom line is producing a result that works for you... which reminds me, I should go post something in the landscape images thread.

Cheers!

[MumbleyJoe]

However, do not always place the right-hand slider at the right end of the curve. Not all subjects contain pure white values.

Indeed! This is partly why I tent to open up the input slider to its highest setting, as the initial points selected by the software tend to try to fill the output range.

[williamtheis]

OK advice but IMHO it doesn't go near far enough... far better to NOTHING in the scan & get a RAW file. Most scanners are 12 bit so a 16 bit RAW is very dark... highest values are no more than 50 (note: not 250!)... do NOTHING in the scanner or RAW converter and bring the image into Photoshop where the control is much better

[mdm]

I must admit, I like the results I have got from adjusting a raw scan, but it is more work so I usually just accept what vuescan tells me.

David

OK advice but IMHO it doesn't go near far enough... far better to NOTHING in the scan & get a RAW file. Most scanners are 12 bit so a 16 bit RAW is very dark... highest values are no more than 50 (note: not 250!)... do NOTHING in the scanner or RAW converter and bring the image into Photoshop where the control is much better

[Bob McCarthy]

OK advice but IMHO it doesn't go near far enough... far better to NOTHING in the scan & get a RAW file. Most scanners are 12 bit so a 16 bit RAW is very dark... highest values are no more than 50 (note: not 250!)... do NOTHING in the scanner or RAW converter and bring the image into Photoshop where the control is much better

The scale you quote ie. 0 to 256 represents the scale of black to white in 8 bit, higher bit scales are overlaid and the actual numbers are not used but assumed.

Bob