| Author | Message | ||
     den Unregistered guest |
In another recent message board thread, it may have seemed that the use of PWP's Filter transform was somewhat disparaged. Most assuredly, it is not and it can be useful in one's enhancement technique. In this same thread, the Levels&Color transform also may have seemed disparaged but it too is useful. See: http://www.dl-c.com/discus/messages/2/5907.html Visualizing image enhancement at the time of a camera's shutter release is not always possible. This becomes next to impossible if the captured image needs recovery from camera setting and photography errors. But if a good image, exposed and focused well with good white balance, is captured, then the enhancing process can be essentially concentrated on producing a superior image from the camera download image. The following is a workflow that incorporates the '3Tone Range Adjustment Procedures' and simulated plus/minus compensated exposures resulting from the use of the Filter transform for the 'capture' adjustments and then uses the Filter transform again with a mask for added 'creative' effects. See: 'Looking Beyond the Lens I' at: http://www.ncplus.net/~birchbay/3Tone&Beyond/beyond01/lens.htm  | ||
| Robert W. Coutant New member Username: Couman Post Number: 96 Registered: 01-2005 |
Another nice piece of work Den! My first inclination for simulating sunlight patches might have been to use the lighten brush. However, your mask/filter approach gives much more control over the detail (and the mask can be fine tuned more easily). For those who are more comfortable using color temperature adjustments rather than inputting RGB values, your sunlight filter corresponds to roughly 5200K. Sometimes, one of the Wratten 81 series filters (with a little exposure compensation) will also work well for this kind of application. Bob C. | ||
| Maciej Tomczak New member Username: Tomczak Post Number: 165 Registered: 08-2004 |
I noticed one aspects of using subtractive self-filter w/exposure compensation >1 and mask to brighten the shadows: it's non-linear and the greater the exposure compensation, the more very dark pixels will become featureless black even as somewhat lighter pixels are brightened. One way around it is to use exp. comp.=1 and adjust amount for for overall brightness (preserving original black, I understand). Curves or brightness have more control in preventing too much of the 'dead black' at the left, if undesirable. Highlights with additive filter and exp. comp. follow similar phenomenon with burned upper highlights. Cheers. | ||
| den Unregistered guest |
BobC... thank you and a good recommendation to use a standard warming filter values... Maciej... a good summary of what to watch out for when using the Filter transform in either Additive or Subtractive methods when Exp Comp is >1. Note the screen shot illustration [Scrn Shot 9] for Step 6.2 includes the ReadOut Tool to check for excessive posterization/clipping. Depending upon preferences, the posterization/clipping can be part of the strategy to impart more 'drama' to the final image version. | ||
| W. Scott Leigh New member Username: Wscott Post Number: 3 Registered: 10-2005 |
Den: Thanks for continuing to provide these workflow examples. I have worked through each of them and I have learned a lot about PWP and how powerful the tools are if you know how to use them. Inevitably I have questions when I finnish. To me the Color Curves tool is one of the least documented and I know I don't make full use of it. In one part of your workflow you increased saturation by moving the 100% saturation point to the left. This would seem to increase all the pixels to the right of the point to 100% but yet I don't see anything that looks over saturated. Why is that? Any hints on how to best use the saturation curve? - Scott | ||
| den Unregistered guest |
Scott... Will need to think about this for a bit as to best illustrate HSV,S and HSL,S Color Curve changes... But a starting point is that the suggested HSV,S curve change in the workflow is essentially the same as the Saturation transform in HSV color space where low saturation is preserved but mid-saturation [slightly] and high saturation [highly] are increased.... Notice the horizontal and vertical axis for either HSV,S or HSL,S Color Curves, they are white [light saturation] in the lower left corner and go to dark [heavy saturation] as they extend upward or to the right.... Like image brightness changes in the HSV,V and HSL,L curves... changes to the initial diagonal line will change the levels of saturation... if the new curve is above the diagonal, saturation is increased and were the new curve is below the diagonal, saturation is decreased.... of course, when the new curve coincides with the initial diagonal, there is no change in saturation. hope this is enough of an introduction.... more later | ||
| den Unregistered guest |
..additional note.... When making changes to saturation, one should also keep in mind that in the HSV color space, 100% saturation occurs at 100% [255 gray scale tone or white] tone brightness and in the HSL color space, 100% saturation occurs at 50% [128 gray scale tone or 50% gray] tone brightness. | ||
| Allan F Unregistered guest |
Den- Enjoy your workflows. Do you have a complete listing of them and where they can be found? | ||
| den Unregistered guest |
Scott.... the tutorial has been revised to link to an 'Addendum 1' that should help your understanding of the Color Curves transform as used here... the 'Addendum 1' htm page is here: http://www.ncplus.net/~birchbay/3Tone&Beyond/beyond01/add1.htm ...but you should refresh the original tutorial page as some other minor comments have been added: 'Looking Beyond the Lens I' at: http://www.ncplus.net/~birchbay/3Tone&Beyond/beyond01/lens.htm AllanF... will give some thought to generating a listing... it is getting time to be a bit more organized.... Thank you both for the favorable comments... | ||
| Jim Lucke Unregistered guest |
I have been trying to improve my understanding of saturation curves in HSV (and HSL) and the principle that, in HSV, maximum saturation is reached at maximum brightness. I have arrived at the following quandary. The definition of Saturation in the HSV color model that I obtained from the Web is as follows: For the cylindrical model of HSV: Let MAX equal the maximum of the (R, G, B) values, and MIN equal the minimum of those values. Then, S = (MAX - MIN)/MAX. Consequently, pure white will come out as zero Saturation since the R, G, B values are equal with the value of 255. Near white pixels will have a small Saturation since MAX is large and MIN is near MAX. In this model, S is not defined for MAX = 0 or black. To test the formula, I took a mountain scene with snow, and I used the eyedropper on Transformation/Color Curves/HSV S to sample the snow portions and they come out as zero or as a small numerical Saturation which is expected by the formula. I also sampled the Brightness in HSV V and the same snow areas came out a maximum or high numerical brightness as expected. The quandary is the principle stated in Den's tutorial that: 'in the HSV color space, increasing the brightness also increases saturation where 100% saturation occurs at the 100% tone [white]'. The snow in my test image is at or near 100% brightness but the saturation is at or near zero -- all in HSV. I would appreciate any clarification on the saturation vs. brightness issue. Thanks. | ||
| den Unregistered guest |
JimL.... you are right... I seemed to have confused 'vividness' [how a color at any given saturation value looks more colorful as it approaches its 100% tone value] with the actual math relationships of H,S, and V.  I need to thinks about this some more and definitely qualify any of the generalizations that were made.... One of the reasons I like to write the tuts is just for this very reason... to make sure I understand things correctly as well... | ||
| Jim Lucke Unregistered guest |
I have been digging a bit more on the Web and the solution to the saturation issue in HSV is to visualize the color space in three dimensions as a cone, hexacone, or cylinder. V is the vertical axis and H and S are the horizontal axes with H measured as an angle from 0-360 degrees (the color wheel concept). S is measured horizontally with values between 0 and 1. In this case, all grayscale tones with R=G=B will have S = 0. All pure colors such as (255,0,0) are at maximum saturation (S = 1) at V = 1 (maximum brightness), with the appropriate angle for H. For example, pure red is assigned H = 0 degrees. The model is much easier to visualize than to describe, and HSV presented as a hexacone is described at http://www.efg2.com/Lab/Graphics/Colors/HSV.htm. I obtained the link from Norman Koren’s website. | ||
| den Unregistered guest |
JimL ... Thank you... I have 'striked' for later revision some assertions made in 'Addendum1'. There is also a brief discussion and illustrations of the HSV, HSL, and RGB color spaces in the PWP manual section Using Color Transfromations, pgs 155->157. With the PWP manual and your link, I now have a good visualation of the HSV color space.... but still need more time for this to jell... Thank you for bringing the incorrect assertion to my attention and my apologies to all if it has been a cause of confusion... | ||
| den Unregistered guest |
Another example of the 'sun dappling' effect technique using the Filter transform is the 'No Fear' image temporarily featured here: http://www.ncplus.net/~birchbay/IMAGEsbyDEN.htm The technique is Step 6 of the workflow here: http://www.ncplus.net/~birchbay/3Tone&Beyond/beyond01/lens.htm | ||
| Dean Sprague New member Username: Dean Post Number: 5 Registered: 02-2006 |
Den, I read your workflow on complex masks and got stuck on the amount of blur. You mention blurring by different percents in each tonal range. I'm having trouble relating your reference to "of the pixel width of the largest masked tone area before blurring" to my images. Can you help me understand how to determine this for images other than the samples? This appears to be a powerful tool. I used it with great success with a strongly backlit image, and with marginal succes on an image of a girl running on the beach. I just can't figure out how much to blur to get the smooth transition without also getting the halo. | ||
| Dean Sprague New member Username: Dean Post Number: 6 Registered: 02-2006 |
Ops, Just discovered that you have answered the above question before. I read your response and am beginning to understand. Sorry for the unnecessary question. | ||
| den Unregistered guest |
Dean... No question is unnecessary to understanding... The amount of blur to use is sometimes just reduced to 'trial and error' for what looks 'best', even for me and I have spent many hours over many different kinds of image content using this approach... A concept to keep in mind is that a 'tone range' mask is being created which is not necessarily the same as an 'image area' mask.... although I will use the 'tone range' masking approach to initially select image areas, then fine tune with the Mask Tool - Paint Brush as needed... ie, sky in landscapes, for example. ...sounds like you are achieving positive results... and hopefully, enjoying the post-imaging process for your images... |
