The harsh truth of Vuescan?

<p>I have used Minolta's software for my Dimage Scan Dual III for over four years. I always had the autoexposure/autocorrection mode enabled. Recently, I switched to Vuescan's advanced workflow (i.e. scan blank leader, lock exposure and film based color) and I find a shocking number of frames on color negative that seem underexposed even after I make adjustments with curves and exposure settings in Lightroom.<br>

I understand that a "flat scan" offers plenty of room to make tonal/color adjustments, and that "flat scans" can be more consistently corrected because you are making adjustments from a baseline (i.e. the flat scan.)<br>

Still, I wonder if the Minolta software has been compensating for my underexposured frames for all these years (many of those frames do look grainy in retrospect...) I want to hear about other people's experiences with Vuescan advanced workflor.</p>

<p>Are you setting your black and white point with the b&W graph? </p>

<p>If you are looking for help, detail what you are doing and ask your question. If you are here to trash Vuescan because something is amiss in your workflow, find somewhere else to bitch. I've been using Vuescan for my film scanning pretty much since it came out, and IMO it is the best software I have used for scanning negatives. For transparencies I think Silverfast may be better, but at a substantial time cost. I think I tried the Minolta software once and got confused by it and mediocre results.</p>

<p>Vuescan gives you the option to do a "raw" scan. You don't want to do that. The concept, as I understand it, is that you can quickly scan lots of images, create a master recipe, then process all the scans in Vuescan with that master recipe. Under normal use, you process each image as it is scanned. By "process," what I mean is corrections to get the slide to a basic state by interpreting the information from the scanner. Is there any chance that you have that option checked? If you are unfamiliar with Vuescan, reset it to its basic defaults. It is far from optimized, but will get you a basic scan.</p>

<p>Bill: I think you misunderstood my post. I'm NOT here to bitch about Vuescan. In the last paragraph of my post, I allude to the possibility that my technique (i.e. underexposed frames) may have been less than perfect, and that the Minolta software has been making autocorrections that mask the underexposed frames. I've done some more tinkering with my scans since the original post, and I've seen some improvement in the color balance. However, the grain is amplified, which appears to confirm my original suspicion about this roll of film (i.e. underexposed frames) Perhaps my title was a bit terse, but this is what I was referring to (i.e. an uncorrected scan can reveal a harsh truth about your technique).<br>

Dave: Are you talking about the shadow and highlight sliders on the B&W curve in Vuescan? I'm not touching those as the advance workflow instructions make no reference to that.</p>

<p>Nope. </p>

<p>Before or after you do a scan, you can go to Image --> Graph b/w</p>

<p>Then you can drag the graph to adjust the black or white points. You just drag the little triangles in the graph to adjusted the histogram. </p>

<p>With my scans at least, this lets me get a better initial dng file (my output of choice) that looks less washed out or flat. Easier for me to adjust everything I want to in Lightroom if I adjust the black and white points in Vuescan first. </p>

<p>I agree that I think this is one way to really understand what your negative looks like if you've been sending out to a lab to print or having software guess for you (like your old driver). I definitely found color shifts and excessive grain when I screwed up and underexposed color negative film. For this reason I tended to keep exposure compensation to +1/2 to +1 in harsh light to ensure I didn't wind up with hard-to-process grainy shadows.</p>

<p>I've started, and stalled for now, scanning color negatives using Vuescan's Advanced Workflow. FWIW, I first output just a Vuescan Raw File, in tiff format.</p>

<p>The Advanced Workflow sets exposure based on clear leader, which <em>should</em> be the darkest you will ever see in a finished image. And yet I encountered one roll where following AW my raw files seemed grossly underexposed. That's where I left off, a few months back.</p>

<p>You need to follow the ViewScan instructions in "Advanced tools and Techniques", "Advanced Workflow Suggestions" right through to the part where you "lock image color". Then you can look at the histogram after a scan, and make any white or black point(s) adjustments, as required. Then scan the whole roll.<br>

If you look at a ViewScanned image without any color balancing, i.e "Color", Color Balance" - none, then the scan will look dark and underexposed.<br>

I don't think that your negs are actually being underexposed. More problems would have shown up by now.</p>

<p>Alvin - What kind of film are you scanning and what does the film look like -- is it under exposed?</p>

<p>I stand by my comment about resetting to the defaults and going from there. Vuescan is a perfect example of "just because you can doesn't mean you should" and I think the best results are obtained by doing as little work as possible in Vuescan and the rest in Photoshop.</p>

<p>Now there is another issue here that you may or may not be aware of. There are two ways to compensate for an improperly exposed piece of film - in the software and in the hardware. I have to wonder if your film is improperly exposed (under or over) and Vuescan is attempting to correct it by adjusting the levels (software) where the Minolta is making adjustments to the lamp brightness. Your comments about your scans looking rough tends to back up the notion that the sensor isn't pulling enough information from the film and the software is trying to compensate.</p>

<p>Is it a fair guess that your images have limited dynamic range (compared to what you would expect) and the transitions between colors and tones is rather harsh?</p>

<p>Could you post up an image that you are having trouble with?</p>

<p>How's your negative scan quality in Vuescan? On my SD3 I seem to have some sort of calibration glitch and I get banding in Vuescan.</p>

<p>Thanks to all for your responses. David: I like your idea, except that it wasn't feasible for the problem pictures in question. The histogram was jammed up on the left side of the graph, thus requiring me to increase exposure. Bill: It's possible that the "clear leader" that I used to measure exposure wasn't optimal, thus leading to underexposure by the software, but I'm not ready to make that assumption yet. All of which leads to my next point...</p>

<p>The problem roll in question was shot on Fuji Press 800. I scanned the entire problem roll and found that the histograms on the first few frames (shot during a rainy, overcast day) were bunched on the left. To me, this suggested underexposure and shadow clipping. The histograms for the sunny frames on the second part of the roll were more centered and normally distributed. Although there was a bluish cast on all frames scanned with Advanced Workflow, I was able to set a proper white balance by first importing the scanned TIFF files into Lightroom, raising the exposure, and then adjusting the white balance. Reversing the exposure and white balance steps failed because there was no true "neutral point" to reference in the underexposed frames.</p>

<p>I intend to scan a few more rolls of Fuji Press 800 to see if this observation holds. I'll post sample histograms once I get through this project. Stay tuned for more posts...</p>

<p>Hi Alvin-</p>

<p>I zoom way in when selecting the "clear leader." That makes it much easier to select it and only it, and not any part of the exposed negative. </p>

<p>I found this tutorial very useful. Thought I would pass it along to you. <br>

http://benneh.net/blog/index.php/2008/04/21/better-colour-neg-scanning-with-vuescan/</p>

 

<p>"Thanks to all for your responses. David: I like your idea, except that it wasn't feasible for the problem pictures in question. The histogram was jammed up on the left side of the graph, thus requiring me to increase exposure."</p>

<p>If that's the "image" histogram vs the raw historgram that means it's properly exposed. If it's the raw histogram you need a bit more exposure. I use the Vuescan advanced workflow and shoot a grey card under mid-day sun to help with color balancing. I also use the tried but true "hand plus 1 stop" for metering tricky scenes.</p>