Question about Chris Crawford's scanning method for BW

[froyd]

I'm following Chris' advice for scanning BW film, and I understand the basic concept of creating as plain (i.e. unaffected by Vuescan's software) a file as possible.

However, I'm puzzled by the curve adjustments. Unlike the white and the black points, which must be set to zero, the curve low and curve high are left at their default values of 0.25 and 0.75. A look at the curve graph shows that these setting provide a straight tonal ramp, which I believe is what we are after. I just wanted to confirm that that's indeed the case and that the curve settings can be left at the default 0.25 and 0.75 values.

Here is the screenshot offered by Chris on his website:

 

[Larry H-L]

Ken Lee's page will help with that.

http://www.kenleegallery.com/html/tech/scanning.php

 

[froyd]

Ken Lee's page will help with that.

http://www.kenleegallery.com/html/tech/scanning.php

This is indeed one of the online tutorial that I had bookmarked and the one that raised my doubts about the Curve high and Curve low settings. I've copied a screenshot from his article where his settings for the curve are vastly different from Chris'.

Bringing the Curve values to 0.001 for both high and low, gives the Graph Curve (CTRL 3) an S shape, vs the flat look of the default setting.

 

[Larry H-L]

I'd try both to see what works for you.

I personally set it a bit differently, I use "color negative" even with BW film, and the make gray from the green channel.

The different gamma settings for BW film/ developer combos can also be very useful for controlling contrast.

I think the most important thing is to not make the scan too contrasty. Go for a wide range of tones, but short of any clipping on the ends.

 

[Particular]

Chris' settings apply a mild curve to the file, which as long as you don't clip any image info is ok. I haven't looked at all of Ken's settings, but he has Color balance set to None, which I believe bypasses the curve. If you output as a tiff a default gamma curve will be added to the file as standard.
I go a step further, and output a raw file (also a tiff), that has no curve attached at all and do all the adjustments in Lightroom.
All these methods will work fine as long as you aren't clipping, or adding radical adjustments that you can't recover from if they turn put to have been too rich.

 

[Bob Michaels]

There are adjustments in Vuescan, such as curves, to crudely mimic what we normally do in an image editor such as Photoshop or Lightroom. These are meaningful only for those who do not later use an image editor and are satisfied with the results from the presets from Vuescan. They mean nothing to someone who will later adjust in an image editor.

 

[mfogiel]

The important thing for you, is to remember to select only the part of negative that you intend to scan, excluding unexposed borders and particularly empty space. In preview, you should see a fairly dome shaped histogram, with both ends being at zero and close to extremities.If the histogram is narrow, and the zero points are close to the middle, you can adjust manually the black and white points closer to the histogram, thus "stretching" it. This way you can take full advantage of 16 bit editing possibilities later. As to scanning in colour mode, I tested this, and it only makes sense if you are using a staining developer, otherwise it is a pure waste of time and disk space.

 

[froyd]

There are adjustments in Vuescan, such as curves, to crudely mimic what we normally do in an image editor such as Photoshop or Lightroom. These are meaningful only for those who do not later use an image editor and are satisfied with the results from the presets from Vuescan. They mean nothing to someone who will later adjust in an image editor.

Bob, what I'm trying to do is bypass the adjustments. I believe both Chris' approach and the one from Ken are both after the same thing. I was just perplexed about the curve settings because a numerical setting of 0 would seem to imply no adjustment, however, looking at the graph, a setting of 0.25 and 0.75 seem essential for linear tone.

Maybe CNNY is on to something, but I'm not sure why Ken would address setting the curves values to 0 if the Color setting of "None" bypasses the adjustment altogether.

The more things begin to look clear in my head the more I'm confused!

 

[Chriscrawfordphoto]

I leave the curves settings in Vuescan alone because the software is so clunky in its implementation of it. I find it near impossible to get good results quickly trying to do it in Vuescan, so I just leave it at Vuescan's defaults and do the curves needed to get good tonality in Photoshop, where the curves adjustments are much easier to use.

 

[froyd]

I think I'm on board up to this point, and I believe I understand the reason why you advise to ignore the curve settings. However, what I'm trying to determine is whether setting curves to 0 captured more detail (to be edited in PS or LR) than the 0.25 and 0.75 setting. Or a different way, is a linear graph preferable to the slight curve that is created by the 0 settings? ...which brings me to another question, why DO the 0 settings produce a curved graph?

 

[Chriscrawfordphoto]

I think I'm on board up to this point, and I believe I understand the reason why you advise to ignore the curve settings. However, what I'm trying to determine is whether setting curves to 0 captured more detail (to be edited in PS or LR) than the 0.25 and 0.75 setting. Or a different way, is a linear graph preferable to the slight curve that is created by the 0 settings? ...which brings me to another question, why DO the 0 settings produce a curved graph?

If your negs are not overdeveloped, you should rarely encounter one that clips the highlights or shadows using my settings. If you do have one with too much contrast due to overdeveloping or very high contrast lighting, set the "Color Balance" setting to NONE and that will capture a much wider range, but with much flatter rendering that will need more work in Photoshop to look good.

 

[Particular]

Having briefly looked at Ken's site, his idea (as I understand it) is to get it as close to right while scanning so you only need to tweak it in photoshop.
I think this approach is a hangover from the days that Photoshop was only 8bit. You would need the scan software to do the conversion from 16bit to 8bit, so you could then edit in Photoshop.
Now you can work in 16bit, there is no need to do any conversion in the scan software. You can work directly on the scan data in Photoshop or Lightroom.
The way I see it, why apply a curve to the data twice if once is enough.

 

[Chriscrawfordphoto]

Having briefly looked at Ken's site, his idea (as I understand it) is to get it as close to right while scanning so you only need to tweak it in photoshop.
I think this approach is a hangover from the days that Photoshop was only 8bit. You would need the scan software to do the conversion from 16bit to 8bit, so you could then edit in Photoshop.
Now you can work in 16bit, there is no need to do any conversion in the scan software. You can work directly on the scan data in Photoshop or Lightroom.
The way I see it, why apply a curve to the data twice if once is enough.

I agree with you. Photoshop is a far better image editor than any scan software, and Vuescan is probably the worst of them all for image editing (but one of the best for scanning).

 

[charjohncarter]

One thing that I do and hasn't been talked about is (at least I haven't seen it from my quick look at all the posts) the histogram. I make sure that the scanning software histogram (B&W) has more than the scanners histogram on each negative. In other words I move the black side further to the right, I scan as a negative so to the right. And then I move the white end to the left, again it is opposite to the inverted histogram. This allows me the more accurately adjust in PS. Here is an example; I wanted complete shadow detail on this shot, and I wanted the bright area at the end of the bridge to also have detail. I didn't want the bright area to be white (255) so I was able to (in PS) to correct to my liking without the impression of blow out. The same goes for shadows, at this end I did go full (0) black or a little more than zero on the dark end:

 

[kenlee333]

My ears are burning 🙂

For clarity's sake, here's my approach in a nutshell, excerpted from my article. It's not a holdover from an earlier era: I use it today.

• Make as few adjustments as possible, since every digital adjustment is "destructive".
• Make important adjustments as early as possible in the process.
• Make adjustments in the analog state where possible: adjust exposure and development first. Then scan. Photoshop (or other editing tool) last.

For the record that I included a section on VueScan after several readers requested it. I prefer the software which came with my EPSON scanner. VueScan's support for a huge range of scanners is wonderful.

 

[Chriscrawfordphoto]

My ears are burning 🙂

For clarity's sake, here's my approach in a nutshell, excerpted from my article. It's not a holdover from an earlier era: I use it today.

• Make as few adjustments as possible, since every digital adjustment is "destructive".
• Make important adjustments as early as possible in the process.
• Make adjustments in the analog state where possible: adjust exposure and development first. Then scan. Photoshop (or other editing tool) last.

For the record that I included a section on VueScan after several readers requested it. I prefer the software which came with my EPSON scanner. VueScan's support for a huge range of scanners is wonderful.

What you're doing has no advantage; your adjustments in the scan software are NOT done in the Analogue state. The A/D converter is in the scanner hardware, and so the data sent to the scan driver is always digital. Some higher end scanners, like my Nikon LS8000ED, do have the ability to adjust the exposure level before A/D conversion. Nikon calls it Analogue Gain. If your scanner doesn't have a true hardware exposure control, and most don't, then there's no advantage at all to doing any adjustments in the scan software.

 

[froyd]

Sounds to me like you are both saying the same thing.

Minimal tweaks in the scanner skewed toward capturing a wide range of tones and producing a "flat" scan. Follow up with "development" via PS or LR to taste.

I took Ken's comment about analog edits to refer NOT to the scanning process, but to the actual film shooting and developing. I.e.: get your exposure right on film and develop gently to avoid high contrast.

While I'm at it, thanks for all the very interesting insights...this has been very informative! A beer on me if any of you fine folks travel through central PA.

 

[Ranchu]

I took Ken's comment about analog edits to refer NOT to the scanning process, but to the actual film shooting and developing. I.e.: get your exposure right on film and develop gently to avoid high contrast.

That's what I read too.

 

[pmu]

I have scanned B&W for years and years with Vuescan and various scanners. After I found out my current method (in 2006?), I have ignored film profiles and numeric values ever since:

Use 16-bit B&W. In the filter menu, click on the "restore fading". This feature helps to give max amount of tones. This and slight generic contrast + histogram adjustment after the scan. Then save. That's it.

EDIT: I noticed that the OP uses "auto save:scan". I would advice against it, because all those fine settings that you are doing are done based on the preview image. Preview image does not show how is the image really going to look like. This is why the contrast and histogram setting should be done after the scan. And then save.