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Pacific Northwest Nature Photographers Tips, Tricks, Techniques & Tutorials

Sharpening Techniques

Sharpening for the Web—Marc Adamus

- Take full res image and reduce size to between 1000 and 1300 pixels. As much as 1300 for detailed forest scenes and such, 1000 for rock and more simple images. Apply "Sharpen" filter (easy enough right?) twice or even three times at 1300-1600 pixels.

- This will create a very oversharpened, noisy, mid-size image.

- Futher reduce image size to your web preference, such as 600 or 700 pixels.

- When reduced, this "tricks" Photoshop into applying an ultra-fine USM that you simply cannot acheive through other methods and all with maybe a 5-10% increase in file size vs. traditional methods such as regular USM or PK sharpener - which is rarely a problem.

- Play around with this technique and make it work for you. Every image is different. Sometimes I'll apply a sharpen filter 3 times at 1500 pixels and then reduce for an even finer sharpness, but other times it has too much of an adverse effect on color and resaturation is necessary. Sometimes I'll just lasso an area and apply the filter more heavily in one section before reducing size. Just experiment!

- Last, keep in mind not to sharpen skies too much as this will unecessarily increase file size. Do local touch-ups with 'sharp brush' to improve textures/definition in sky and water!

Sharpening Tip—David Bostock

One trick to sharpening I like to use is this: Whether I use USM, NIK, or some other technique, once I sharpen, right after, I select Edit, Fade...from the menu. This brings up a dialog with Opacity and Mode options. I generally leave Opacity alone, but change the mode to "Luminosity."

This accomplishes the same thing as changing the image mode to LAB Color and then sharpening the Lightness channel, but without going through the conversion process. I find it significantly reduces the halo effect.

Increasing Dynamic Range

Digital Gradual Neutral Density Technique 1—David Bostock

Here's a technique I use all the time for images where I want to selectively control the curves, levels, or contrast. Say I have an image where the sky's too bright, but the foreground's too dark. I'll Choose the "Rectangular Marquee Tool" from Photoshop's tool box and draw a selection box around the top part of the image. Then, I'll choose "Select, Feather..." from the menu and feather by 100 to 250 pixels. This creates a graduated selection. If you've selected the entire top and upper sides of the image, then the only part that gets featherd is inside the image itself.

Then, with the selection still in place, I'll adjust the sky with curves, levels, contrast or another tool. You can apply as many adjustments as you want.

Then, I choose "Select, Inverse" from the menu. The selection automatically moves to the bottom area and I do my adjustments again.

I've also tried selecting smaller areas on the image and feathering at 50 pixels or so...it works nicely.

Digital Gradual Neutral Density Technique 1—Mark Hudon

I learned this from Swami and he says he found it on the internet.
Take two photos, one exposed for the light parts of your scene and the other exposed for the dark parts.
Take your two photos change them to 8 bit.
Adjust the two images like you would any other photo aside from sharpening. Adjust the part of the photo that is going to be seen in the finished photo.
Get the photos to about 65-70% of where you would want them if you were going to use them as individual photos. Make copies of these versions and flatten them.
Take the darker photo and, holding the shift key so that they line up perfectly, drag it onto the lighter photo.
Make a layer mask on the darker photo.
Click on the new layer mask but don't Option/Alt click on it.
Grab the gradient tool. The gradient goes from dark to light. The dark will become transparent. So, in this photo, the correctly exposed Mt Hood was on top so that's what I wanted to keep. I drug from the bottom to the top. The bottom became transparent and revealed the correctly exposed foreground.
A trick of the gradient tool is that the fade will be from where you first click to where you click again. If you clicked about a quarter of the way up the photo and then again three quarters of the way up, The bottom quarter would be transparent, the middle two quarters would be the fade area and the upper quarter would not be transparent at all. Additionally, the fade will be perpendicular to the line of the two clicks.
My technique is to try something and delete it if I don't like it. It's sort of hit or miss.
After I got a blend that I liked I duplicated the photo, flattened it, did some burning and dodging, hue and saturation, levels, etc.

I just discovered that you can do more than one gradient on the same mask! I'll bet this would work on, let's say, a very deep canyon which has sky all the way down to the bottom but to expose for it, you'd have to darken the canyon walls on both sides quite a bit.

Tips, Tips, Tips...

Layers from Selections—Gary DeWitt

David Bostock, in his "Digital GND Technique" message, above, mentions feathering with the marquee tool. Here's another way to accomplish the same thing that, in addition, lets you make adjustments in layers. I like to do all my adjustments in layers so that I can change the adjustments later one.

Create a selection using the marquee tool, lasso tool or magic wand. Don't feather the selection yet. Then, from the Layers menu, choose New Adjustment Layer and select the type of adjustment you want to make. I frequently do this with Levels in order to mimic darkroom techniques such as "burning in" or "dodging." At this point I simply click OK in the adjustment dialog without making any changes, yet. The beauty of layers is that you can come back to it. Open the Layers palette and note that a layer mask has been created for the new layer. Alt-Click the layer mask and you can see it in the image display. Only the white part of the mask is affected by the adjustment in the layer. Now you can use Gaussian Blur to "feather" the layer mask. The nice thing about using this is that you can easily see the effect of your feathering, rather than the somewhat more hit-and-miss technique of setting the pixel size of the feather.

Now if you wish to inverse the selection, as David mentions, go back to the image and reselect, then inverse and repeat the process. Now you have two adjustment layers, each with a layer maks, each layer mask is blurred and they are inverses of each other. If you wish to do other adjustments using the same layer mask, then you can copy the layer mask to the clipboard and paste it into another empty layer mask.

Scanning & File Formats—Gary DeWitt

Once I scan I save the untouched image as a TIFF. One nice thing about the format is that it is a bitmap that offers lossless compression. I scan my MF film on my Epson 3200 at 1500dpi, doing two passes at different gammas to try to get a usable dynamic range. I'll then be combining the two passes into a single image, which I flatten and save in PSD format. This is the file I will later do all my work on, so the PSD format allows me to use and save layers.

PSD, with only one layer, is about the same file size as a TIF, so if I didn't have to do multiple passes to make up for the deficiencies of the scanner, then I would feel as much need to compress the originals when I save them. But since every slide has two 50MB TIFs, plus a combined image in PSD, the space requirements expand rapidly.

BTW, I also have a Nikon Coolscan IV ED which I use for my 35mm slides and negs. I feel no need to do multiple scans with it as I'm happy with the scans, so I don't have to do nearly as much work. I really wish I could replace my Epson with a Coolscan 8000, but 1.5 years without a pay check is starting to drag on the ol' photo budget.

Remembering—Mark Hudon

Here's a tip to help you remember what you've done to a file after a bit of time has gone by.

I usually sharpen a composite image when I'm ready to print. You could have dozens of composite layers, all sharpened for different sizes ready to go at a moments notice.
To make a composite, add a layer above all your other layers. Hold down the option key (alt on Windows) and click on that right pointing triangle in the upper right corner of the levels box. Choose Merge Visible. Since you have the option/alt key held down the program will actually create a composite layer of all the visible layers below it.
My tip is to double click on the name of the layer and enter "USM" (to siginify that it's a sharpening layer) and the values of the USM that I used, i.e., USM 85, 2, 4. This way you know how much sharpening you used. You can go back, delete this layer or add other sharpening layers and still know, years from now, what you did!

Got a tip? Send it to PNWNP Regional Coordinator.