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Home > June 2003 > Tips
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Digital Photography: HowTo
Revealing Hidden Details
By Richard Brown
Digital photography offers a uniquely immediate, digital version of our world, but it takes a digital darkroom to make digital snapshots into photos.
When considering digital cameras, they vary greatly in their ability to capture images. The techniques weÕll take a look at today will allow you to quickly find out the nature of your own camera, and possibly shed some light, quite literally, on getting better results from your digital photos.
This picture was taken of a remodeling job with the Fuji Fine Pix Pro S1 using a wide angle lens, hence the apparent keystoning effect. Note the abyss at the top of the frame. Automatic white balance partly caused the white door to go blue, but really, when a wall is missing, and skylight out of direct sun provides all your illumination, the extreme blue shift due to the color temperature of such light would give regular Kodak film a run to hold a natural balance.
First, to do something about the abyss. On to Photoshop 7 to do some magic.
Using the Polygon Selection Tool, I select the black abyss, including a little of the framed area to the right side of the door. The crawling ants delineate the area, and once selected, under the ÒSelectÓ menu, I choose ÒFeather,Ó which brings up the Feather Radius dialog box. As the image is high resolution, over 17 megabytes, I can use a fairly decent amount of feathering to better blend the transition area. I choose a 10 pixel radius, then do a copy and paste with Command-C and Command-V, although I know some might call it ÒApple-C, Apple-V.Ó
To Copy and Paste in Photoshop 7 causes the selected area to be copied and then pasted into its own, new layer, named Layer 1.
Taking a look at the just-copied abyss in Layer 1, and we see that the abyss is the only thing present, the checkerboard pattern indicates transparency.
The beauty of using layers involves many things, but here, IÕm going to use a simple trick involving blending modes. In the Layers Palette, all layers default to normal, opaque mode. Clicking on the button drops down the many choices for blending. Here, I will choose ÒScreen.Ó This mode will serve to brighten the underlying layer according to the value of the overlying pixel. A photographer might call it Òopening up a stopÓ digitally. A traditional chemical darkroom photographer would liken this, in printing a negative, to dodging or masking, except digitally itÕs faster, much more accurate, and with much more finesse.
In selecting ÒScreenÓ as the blending mode for Layer 1 (the abyss), the image improves. Everything is a bit brighter, and in fact, the back wall is already pretty much to my liking, but the abyss of the ceiling needs a lot of help. A screened layer can be duplicated simply via right clicking on it and selecting from the contextual menu, which I doÉ but the back wall gets a bit too bright, so I decide, now on Layer 1 Copy to delete some of the screened pixels.
I just select the Rectangular Marquee tool, and select the wall area, along with a little of one of the bright-enough 2x4s by Shift-Selecting a second rectangular area. When youÕve created any selection in Photoshop, you can add to it by holding down Shift, or subtract from it by holding down Option using any of the Marquee or Lasso tools. Note that the decision to delete some of the screened area involves no guesswork, as you always can see the current result and decide to make changes based on it.
Once selected for deletion, I once again add some feathering and hit the delete key. This results in a new shape, essentially the ceiling area alone, which can now be duplicated as many times as needed to reveal available shadow detail.
And this begins to make the point: some digital cameras retain significant information in the shadows. The Fuji Fine Pix Pro series offers tremendous shadow detail, and so I continue to duplicate the abyss of a ceiling until it is revealed to my liking. This takes four iterations to suit my taste, which is to say, four vertically stacked copies, all using Screen blending, to reveal the ceiling, which turns out to have been ripped out like the walls, just a bunch of boards awaiting a new ceiling.
And this brings up the second stage of this image tweaking, wherein the right side wall seems a bit dark. Thus, as before, using the Polygon Lasso tool, I simply select the right hand wall area, feather, copy, paste, and create Layer 2. Selecting Screen blending, the wall suddenly looks about right, excepting the near edge board is getting too bright.
No problem. Unlike blowing a dodging routine in a chemical darkroom, this brightening effect can be adjusted at any time. A layer screened over another layer can be infinitely adjusted in terms of intensity of the effect by simply changing the opacity of the screened layer. In this case, I cannot use opacity because it is just the leading edge, a single board in the image which is too bright. Once again, simplicity itself. ÒIf it offends thee, cut it off,Ó I believe the saying goes. So, I grab the eraser tool and size it to a soft 200 pixel diameter (remember, this is a 17+ megabyte image) and then, with a nice feather, erase away the offending brightness.
Now the walls and ceiling area look pretty well adjusted, I note that blue door sticks out all the more. The door needs to be brighter and less blue. Why not continue with Screen blending, only now, with color options? In many situations, Photoshop offers more than one solution to the problems at hand.
Once again, the Polygon Selection tool, selecting the door. Then feather, copy, paste as before. Selecting Screen blending has way too much effect on the white door, so its opacity is adjusted until the lightening effect becomes satisfactory.
 At this point, IÕll introduce another tool, the great and allÐpowerful, well, perhaps not, but the most useful Selective Color tool, which can and does work wonders. In this instance, a white door with a blue cast needs correction, but a little trial and error reveals that adjustments to the NEUTRAL tones begins to deliver the results in combination with the screened layer. Adjusting the color until the screened pixels color correct the underlying bluish door can quickly be determined by eye, with the result, of course being updated real time with every tweak. Soon, the door is looking far more neutral, but not weird.
The problem with the digital darkroom can be defined as Ògoing overboard.Ó If you can live by the Òless is moreÓ principal, youÕll be happier with your digital results.
Now the door no longer sings the blues, I note the planks of the floor do not match my mindÕs eye. Did I mention this was MY renovation? The chalkiness does not quite fitÉ so once againÉ the same technique as the white door.
Creating the new layer, I once again use the selective color control, and tweak a little wooden life back into the planks. And so, we have a better image, pulled from the abyss and back into printable shape.
And now, to step way, way back for a minute.
Digital workflow, from camera to computer to final presentation, needs to be considered at the outset. That means every time you pick up your digital camera. If the web and pictures in email are your only interest, low resolution can be just fine. But when you want to keep a photo as a print in a photo album, you basically have to set the camera to its highest resolution every time. ThatÕs the resolution where your camera says it can only take 6 images or so, or more if you have a big memory card. Even when you do this, you are almost always pushing the limit to get to 8x10, which at a reasonable photo resolution of 240 dpi requires 1920 x 2400 pixels. ThatÕs basically a five megapixel camera at max resolution. Moving up to CMYK printing press applications (300 dpi), and the five megapixels run about 30% short when it comes to 8x10s.
On my Fine Pix S1, I get 5,354 images at low resolution. But I print everything, or do sophisticated manipulation where resolution counts even if going back to the Web in final form. Thus, I shoot in only two modes: uncompressed, which, on the same microdrive, I get 56 images, and in hardware first level compression, which is about an 8:1 compressed JPEG and yields Ð do the math Ð 422 images.
While it is possible to Òup-resÓ your files, going more than 200% using standard algorithms begins to truly look bad, and with specialized software like Genuine Fractals, youÕre peaking around 600%.
Hope you enjoyed this little forayÉ thereÕs much more to come. |
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