Hmmm. Interesting. I use the channel mixer as well. But I start from a much different position: 90 red, 8 blue, 6 green and -4 constant. I tried your starting combination on my laptop, and the results were similar but less contrasty. But I have to experiment on my photo computer, which has a calibrated monitor. It's interesting, however, that radically different settings don't produce radically different results. Paul On Dec 17, 2006, at 5:00 PM, Godfrey DiGiorgi wrote:
> I have a good workflow for B&W conversion using Photoshop CS2 that > has been producing excellent results for the past year or two. I use > a variant of the "Channel Mixer" formula, working entirely in > Adjustment Layers. Some of it is actually automated, but some > decisions have to be made per picture as well when you get to the > finishing stage. The concept is fairly simple ... the devil is in the > details. > > Here's the fundamental idea: > > - Be sure you're working on a well calibrated monitor and know how to > use profiles in printing. You can't make a decent print consistently > if your system is not calibrated properly. > > - When you apply RAW conversion processing, don't make the mistake of > presuming that you're going to make a perfect conversion that needs > no further editing. Seek to output into RGB *as much data* as your > image file contains, and presume you're going to be shaping and > manipulating that data later. This means [EMAIL PROTECTED] output to RGB > in PSD or TIFF formats. > > The rest of the workflow is at the RGB channel level so applies to > DNG, PEF, PSD, TIFF, or JPEG files equally. Of course, if you're > working in JPEG files, due to the [EMAIL PROTECTED] nature of the files, > editability is less, but that doesn't mean the workflow breaks down. > > 1) Look at the photograph before you begin and decide what you want > to do with it. High key, low key ... decide where the IMPORTANT > details are and where you are willing to let highlight and shadow > detail go away. This is *the most important* step ... You cannnot > achieve a goal without knowing what it is. > > 2) I apply via a script an Adjustment Layer using the Channel Mixer > tool with the settings R=20, G=70, B=5 percents. This is a starting > point and not necessarily the best mix for all scenes. You can get a > feel for how to manipulate this by turning the adjustment layer off > and then looking at each channel in B&W seperately for a moment (the > Cmd/Cntrl ~, 1, 2, 3 keypresses let you do this very quickly and > easily). Tweak the Channel Mixer settings to suit where you've made > decisions about how you want your photo to appear in B&W ... if you > have a lot of detail in the Red channel and not much in the Green or > Blue, bias the mix to Red. etc. > > 3) If the image has several different kinds of lighting in it that > changes the ideal mix in different areas, you can either > > - insert Curves adjustment layers under the Channel Mixer layer and > tweak the curves for each channel independently, with masking to > separate the different areas. > > - Mask the channel mixer adjustment layer and use a second or third > one to change the mix, with masks again to localize the differences. > > (I tend to prefer using this Curves technique as I find it easier to > compress or expand a tonal gradient with it. In general, I use step > three about 20% of the time.) > > At this point you should have a close-to-final rough of your B&W > rendering. Up to here, most photos will look like what you get from > processing B&W film at a photofinisher. NOW it's time to make your > image shine. ... Study your image again and identify what needs to be > done to reach your goal. > > 4) I usually do overall sharpening for the full resolution image at > this point as it will change local contrasts and edge effects that > you want to take into account when doing tonal edits. Select the > background layer, make a layer copy (no destructive edits to the base > image...) and use CS2's Smart Sharpening tools. Small adjustments > applied incrementally work best. Watch the important areas of the > image at 100 and 200% scalings to detect haloing and artifact growth. > Back off when you see them ... they look unnatural. Different images > require different sharpenings... > > 5) Now, back to tonal shaping. Curves Adjustment Layers with masking > inserted *above* the channel mixer adjustment layer will operate only > on the grayscale tonality. Again, small steps, one area at a time, > with selective area masking ... I watch a particular area, get it the > way I want, then fill the mask with black and brush in the adjustment > with a soft edged brush and a slow fill rate until I get it the way I > want. I build up each area of the photograph in this fashion, a > little at a time, merging layers as appropriate when I reach certain > points to simplify the document and save space. > > 6) Once you have everything done as well as you can manage, the rest > of the workflow to render for the web is pretty fast. Be sure to save > your work in PSD format to preserve all the layers (you should be > doing that often throughout the editing process...). I do a profile > conversion to sRGB, which auto-flattens the layers and uses the full > 16-bit data in calculations. Next, from Pentax full-resolution files, > I use "Image->Image Size.." and resample the image to either 620 > pixels for a horizontal or 530 pixels for a vertical, let the other > dimension fall where it may, and set 72ppi as resolution (helps with > some of the applications I use that honor the density and sizing > information for on-screen display). At this point, you will often > notice that the image has gotten a little darker. A Curves adjustment > layer to tweak the tonal curve upwards, reflatten again. Sometimes a > minor application of USM (.8 pixels, 30-40%, threshold=2) to > resharpen. Then use "Image->Mode->8-bit" to reduce it for JPEG > output, and "File->Save As..." to JPEG, quality 6. > > You're done. > > The key isn't just to follow the formula. The real work is: > > 1) Evaluate the image and understand your goals in rendering it to > B&W. > > 2) Understand what each of the steps is meant to do so that you can > modify the processing to suit a particular image problem. > > > I'm also experimenting with Lightroom's B&W rendering tools, but I've > just started there. So far, I get more flexibility and better > rendering with my workflow above, but it might just be a matter of > learning a new way of working rather than any issues with Lightroom. > > Godfrey > > On Dec 16, 2006, at 12:52 PM, Toine wrote: > >> I'm experimenting with several techniques for B&W renderings. I tried >> the channel mixer. At the moment I'm experimenting with the adobe >> primer: >> http://www.adobe.com/digitalimag/ps_pro_primers.html >> Most exposures give nice results and impressing Epson R2400 prints. >> I fail to get the results I used to get with tri-x and orange or red >> filters. Most difficult is creating a dramatic sky which was easy >> using a red filter: >> http://leende.net/galleries/trix.htm >> Do I need to tweak my exposure settings, RAW conversion or use orange >> and red filters. Would you like to share your B&W conversion secrets? >> >> Toine >> >> -- >> PDML Pentax-Discuss Mail List >> [email protected] >> http://pdml.net/mailman/listinfo/pdml_pdml.net > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
