Paul,

There's a notable difference between citing her workflow and quoting her opinion that the other options as "That's all a lot of bullshit for people with too much time on their hands.". Her workflow may work for her, but her descriptions of the other options is flagrantly wrong, and your description of her methods indicate she simply moves the requisite adjustments to a different portion of her workflow.

That said, you simply cannot adjust colour response after the conversion. She's obviously doing it prior to the conversion or not at all. Once the colour channels are gone, your colour response is fixed. You can tweak levels and curves all you want, but you will not be able to differentiate between a formerly red pixel that gives a certain greyscale level and a green one that gives the same level in the fixed conversion.

-Adam

Paul Stenquist wrote:

I'm not tryng to score debating points Adam. Merely citing an example of how one very good retoucher works. She can alter the color response very effectively by changing the color before conversion. She can also do it by masking individual areas -- a sky for example -- and altering the tonality after conversion. Her method isn't necessarily simple. It can be quite complex. I only mentioned it as an aside. What I did say was that you can achieve a very nice conversion by using the photoshop grayscale conversion and then applying tonality adjustments with curves after conversion. It will give you results that are indistinguishable from what can be achieved with the channel mixer in most cases.
Paul
On Oct 31, 2005, at 8:47 PM, Adam Maas wrote:

Paul,

That's an argument to authority. And incorrect. I'm sure she's quite competent, but in this case, she's also wrong. This is the sort of argument that I see very often among computer consultants.

Simply put, her method simply can't deal with an image that would require filtration with B&W film. Even my basic channel mixer method (which takes maybe 10 seconds longer than her method for most images) allows me to balance the three channels to taste. Her method allows tonality adjustments to the final mix, but absolutely no adjustment of colour response which, as most serious B&W Film shooters will attest, can be extraordinarily important to a final image. considering that many people used to choose film just for it's colour response (See the difference between SFX200, Tri-X 400 and an Orthochromatic emulsion for starters)

-Adam

Paul Stenquist wrote:

No, you're incorrect. My retoucher friend knows exactly what she's talking about. She does fantastic work and is in great demand among pro shooters at about $200 an hour. Sometimes she will go back and alter the color image to change the conversion , but she's more likely to tinker with it after the fact. She frequently uses curves and masks after the fact if more control is needed. But she points out that the PhotoShop grayscale conversion provides an accurate translation of a given color scene. It's quite close to what the values would have been if shot without filtration. She did the conversion and some after the fact tuneup on my shot of the shoe shine man. http://www.photo.net/photodb/photo?photo_id=3451662

On Oct 31, 2005, at 5:25 PM, Mark Roberts wrote:

Cotty <[EMAIL PROTECTED]> wrote:

On 31/10/05, [EMAIL PROTECTED], discombobulated, unleashed:

Thanks to all who commented. By the way, this BW conversion was done the
fast and easy way: A simple mode change to grayscale followed by
adjustment of the tonal range in curves. In that this simple procedure allows complete control of tonal range and that any more elaborate method takes you to the same place -- grayscale -- I fail to see the need for elaborate "recipes." I mentioned some of these elaborate procedures to a
professional photo retoucher a couple of weeks ago. She simply said,
"That's all a lot of bullshit for people with too much time on their
hands." That being said, I sometimes use the channel mixer because it's
fun. But I don't think it's necessary.



That's very interesting you say that. I have often suspected it.



But it ain't true. This "professional photo retoucher" doesn't know what
she's talking about. There are some tonal changes that can *only* be
accomplished before the image is converted to grayscale. That's why
those of us who use B&W film often use color filters when shooting.

A trivially simple example: You can paint an object in 3 shades of gray, red and green each of which will translate to exactly the same shade of gray with a particular B&W film or greyscale conversion. Once the image is in greyscale, you can play with the levels and curves controls until the heat death of the universe without them ever changing in relation to
each other, but using a color filter when shooting B&W film, *or*
adjusting color balance in Photoshop before converting a color image to greyscale, will give you control of their relative density. This applies to all colors to some extent, and control over these characteristics are
what the channel mixer procedures and other recipes accomplish.

What you're dealing with isn't "bullshit for people with too much time
on their hands" but rather "bullshit from a photo retoucher attempting
to conceal a lack of understanding of some very basic photographic
concepts".

BTW: You can't use digital color balance changes to *exactly* duplicate the effects of a physical color filter applied during shooting, but you
can get pretty close (and that's an entirely different discussion.)


--
Mark Roberts
Photography and writing
www.robertstech.com



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