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I don't use Epson scan unless I was doing some software testing to see if my stuff works with Epson. But I would choose option 3 if working in 16 bit, and assign an appropriate profile in a photo...

Of all the options that is one Not to choose unless you had a specific reason to do so. I.e. that is the one that will clip some of your values.

It is a pigs breakfast! A good example of ancient software, but what are the alternatives...

The first option allows you adjust white and black points, essential for 8bit scanning (obsolete) but...

Possibly, I just used the film leader, and for 4x5 I just had many spare sheets that I forgot to press the shutter, before I developed the film... A long as you get around 80-90% that is fine. Its...

I will try and find some test shots of grey scales that I am sure I created with HP5. I do my testing and software dev with color film, and real photography in black and white. If your shooting in...

Ok so take that value divide by 255 and you have the raw value, without gamma applied its 92.16%.

If we imagine that value represents the light hitting the sensor in a give time by the hardware,...

the L is very complicated formula that attempts to model human perception and includes colour in that percetpion, but the input is the real values that can measures with instrumentation. In the case...

Lots of simple photo tools, even a text editor if you use an image with consistent density, e.g. clear film, Photoshop probably as well but I never use it, if I measured your graph at 92%. Then in...

Using L in photoshop in THIS instance will probably just confuse you if you don't understand the underlying formula.



No I as mentioned earlier I wrote some software to do that, but for 4x5 it...

No it looks good, if you look at the raw file outputted it should look white or have values close to white, it might vary a bit depending on what program you open it with.

If you scan RAW it...

No the film base being the most transparent part of the image will let the most light through, this will give the highest value on the sensor. i.e. close to "white" or "1" if your using normalised...

Yes, removing the lock exposure reveals the slider, and then you can manually control the exposure. If you don't do that it will use the value calculated from the last preview scan. This is downside...

Neither, it adjusts the timing of the logic gates that clear the sensor, and gates that take charge from the sensor to the A/D to give a number. A bit like adjusting the shutter speed on a FP shutter...

Always RAW, however depending on what options you actually choose there isn't much difference, but it it depends on what options you actually choose... That is actually why I like vuescan, as I...

or just select the whole area, or a large enough area to be sure. The scanner always scans the whole width, if I have two 4x5 images I still just scan in one complete pass. I wrote my own software...

I have a 4990 I found the optimum focus is slightly above the glass. Mine was about 1.5m, I think, FWITW... With a wide lens, the depth of field is not as critical as the longer lens that the...

Just skip the preview button and just press scan only, that is the most compelling feature of viewscan IMHO. I have a profile for each type of film i scan. So if a have 20 sheets of HP5. I can scan...

As far as I can tell, Each sensor is being "reset" so that "1" equals the maximum intensity, so the output is a "digital white" 1,1,1.

Using vuescan you skip this step entirely.

You should choose gamma 2.2 (though it doesn't really matter if your working in 16bit and correcting your image in an image editing programme). Or you can choose the no color correction option, and...

I spent years printing RA-4 some of it making a living... I also understand the inner working of a lot of the software you discuss so I can describe in technical detail roughly what is happening in...

When you deconstruct what your actually doing here. It is pretty much what happens when you open RAW file from a DSLR on your PC with the exception of the demoscacing. i.e. your calibration applies a...

A monochrome sensor will capture it too :-) In the end it is about reducing metameric errors. None of these sensors old or new match the eye. They use one or more colour matching functions in their...

I didn't write that post but I am the OP. I took what Calebarchie was saying is that most drum scanners used a "densitometric" approach rather than "colormetric" approach. I.e. for the former measure...

Here is an interesting article, you even create movement masks so that pixel shift can be used for moving objects. (it uses one the image for the moving parts of the imaging)
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I looked at the Pentax K-1 II, (some one sent me so files). You can shoot RAW with pixel shift, I created a new 'combined' RAW image easy enough, or you can create a regular RGB tiff file. It might...

Yes, just interested in how you do stitching, always impressed with what can be done.

Looks good Peter!, is the stitching automated?

Next we will be discussing if the moon landing happened... :) In the absence of the actual chip design, there is plenty of documentation that says it has this feature, it can be even found in the...

Sure you have to have an exposure time that allows for enough photons to be collected to create a measurable voltage, that will register on the first stage of the A/D convertor. The longer you wait...

Dmax has nothing to do with how bright the light or how sensitive your sensor is, you can have a very bright light and very very sensitive sensor but poor Dmax.

These are stepper motors that don't have a speed, like a normal motor, they step, when told to step. When the scan line is completed they step to the next position. In order to position the sensor...

These are two crops of 35mm underexposed Kodachrome 64, nothing at all special other then sentimental value from my Epson 4990-


https://i.ibb.co/thjj6nq/straigh-scan.png
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Peter,

I found for 35mm kodachrome, with exposures all over the place (often 1 stop under or more) using the "2 exposure HDR scan option" was a no brainer, the S/N ratio in shadow areas was...

Vuescan with epson V series and 4990 all have 2 exposure HDR options, it is just called something different :-)

It is only needed with transparency, its a simple and very effective improvement...

For color negative, as opposed to colour separations from positive originals:

#70, #98, #99 but keep in mind the paper already has sensitivity that already matches these with broad spectrum light...

No doubt your very skilled, and like other contributors, that is a resource that prompts me to ask questions.

It might be worth considering, while portra is suitable for making internegs from...

Your V850 will cope easily with any of you BW negatives. If you listen to the advise given by others here, you will be able to make good prints.

If you want to use your scanner as a densitometer,...

The Bayer array makes it hard yes, and the IR cut filter harder still. My prototype is functioning, but not yet a success. :-) I have not modified my DSLR, and hope to avoid that if possible.


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Sorry if my previous post appeared antagonistic, appreciated those comments you made earlier. I have collected numerous articles and several academic texts, as you suggested.

This BTW visually...

Not really IF you isolate the problem. The interaction between color negative and the color positive/inteneg/pos is remarkably consistent. i.e. nearly any color paper will work with color negative....