Turning Archive 2004

Image editing tips (LONG)

Mike Schwing from Md.
>Nobody asked for this, but in response to several/many requests both here and in email, I have detailed my basic procedures for preparing an image for upload. If this helps even one person, great. If not, thats OK, too. I am not a pro, but I have been doing this for many years for several different hobbies and sports. Comments, additions, improvements all welcomed, maybe we can improve on this and get it posted as an article somewhere....
Photo editing/posting tips.

I possess nothing other than self claimed proficiency at photo posting on the web, but enough folks have asked me for help that I thought I’d put some tips together that I employ when composing/editing/posting pictures for website posting.

These tips are written around a few popular woodturning sites in particular, including Woodcentral (www.woodcentral.com) and the AAW website (www.woodturner.org)

Why so much detail, time spent in photo composure/editing? The way we communicate our work with each other on the woodturning webs, in effect the language we use, is through photos. A clear, well composed and displayed photo can show our work’s profiles, finishes, details, and flaws in ways that a poorly composed one cannot. Why not use the best language possible?

I won’t go into actually taking the photo because I am far from qualified to discuss that. See John Lucas, Jamie Donaldson or other photography experts in the web wood turning community for help with that topic. The only thing I will suggest about the photo taking subject is to save your images in a file format that will allow for the highest quality you can reasonably store on your camera, TIFF format is great, but has excessive file size requirements (5meg or more), the SHQ (super high quality) on my Olympus camera produces very acceptable images at a few hundred Kb each. Standard quality will limit your editing success.

Typically, digital images fresh off of the camera need some editing to give them the best appearance possible. The things that generally need work are – image size – both in width/height as well as file size, cropping out unwanted areas, altering brightness/contrast, and sharpening. Color balance is often required to remove unwanted blues, greens, or reds, but this is a task that can be frustrating (especially if you are red/green colorblind). Some/most applications have an auto color balance feature, but more often than not I wind up “undoing” it they seem to highlight blues.

Image format is also an issue. JPG (jpeg) files are the most common, and probably best suited for photography work to be viewed over common web browsers. PNG is a newer standard that allows for automatic scaling, and it works well but doesn’t seem to be catching on, and might give some browsers trouble. It also produces a larger file size that might be cumbersome for slow web connections and storage. Do not use .BMP format.

What size should you make your images? That is a “depends” question, of course. Monitor sizes and screen resolutions vary tremendously. A 800 pixel wide image might take up the entire screen on a small monitor with a low resolution setting. It might, however, only take up a very acceptably small portion of a 19 inch monitor set at a high resolution. Larger files also take up more space, storage wise. A compromise has to be met between the file storage available and the viewing size (as well as image quality). In order to use WoodCentral’s file upload feature, images must be limited to 40K in size. For me, I find that an acceptable compromise of image display size, about 550 pix wide, and a quality setting of about 75% produces a good looking image at about 39Kb, just large enough to make it into Woodcentral’s storage system. One can post larger photos on WC, but they have to be hosted separately. The AAW site allows for 80Kb file sizes, giving a little more flexibility in your image options, but the same issues apply. Very few people have monitors, and adapters that can display really discernable differences in images that are saved in the upper realms of image quality, but the difference in file size can be huge. The image quality factor – something that is available to you when you save your file, in the upper reaches, from about 80-100%, makes no real appreciable improvement in the photo, but the file size can jump from 100K to several megs. If you post photos that are too wide for viewing on most people’s monitors, you’ll hear from them. No news is good news.

The applications -

I’ll stick to shareware/freeware applications that you can download from the web. These are the ones I use. I’ll describe the apps, and how I make use of each.

Polyview (www.polybytes.com) A fully usable version is available for download at their website. The trial license expires but the product never ceases to function. I’ve traditionally used Polyview for image viewing, as it has a great thumbnail viewer, and can even make thumbnail images and index pages. It also has a nice slideshow feature. (minds out of the gutter, please) When I upload a disc full of images for editing, I first view them in the Polyview thumbnail explorer to see which ones are the best candidates for further editing as it allows for viewing the entire image set side by side. Recent versions of Polyview have made great strides in the image editing arena, and it is now possible to do things in Polyview that used to require AC/DSee, Photoshop or a more professionally oriented application. If you are unfamiliar with digital image editing Polyview is a good starter choice as far as I am concerned. Simply find your image, open it up, and all of the options are available via clicking the right mouse button on the image. A hint – I prefer to edit my photos in the size which they will be viewed. Many image editing programs will display your image on the screen in half or other size. The amount of color/contrast in an image can seem DRAMATICALLY different in the full size photo vs. a smaller version. If you’re like me, you will make sure the image is being displayed at 100% (full size).

The Gimp – (www.gimp.org) A MUCH more powerful image editing program. It is basically an open source, free version of Photoshop. It can be a little quirky, and it is definitely a horsepower and memory hog, so if you have an older machine – it will be very cumbersome and frustrating. If you have the power, however, and the time to learn it, your results will outshine what you can do with Polyview. There are web forums devoted to The Gimp, and lots of help and online tutorials available. Most of the features available in The Gimp are outside of the areas we will be concerned with for digital image preparation, but they are there should you desire them.

My steps in editing are as follows;

1. Cropping. First I crop the image as needed. To my eye, an image appears better if it has more “sky” above the work than ground below it. I keep this in mind as I crop the photo. The work also appears better, to me, if it is evenly placed in the center of the image, so I try to keep the vertical edges evenly spaced from the widest part of my work.

2. Scale. Next I will scale the image for the display size I wish to present to the viewer. If I’m preparing an image for multiple sites with different size limits, I will work with the largest size, then when I’m happy with it I will save it multiple times in different image scales. My personal preference for WC is 550 pixels wide, and I usually let the image editor manage the height automatically to preserve the image proportions.

3. White/Black points I set the white and black points. I don’t usually see any improvement by setting gray point. Both Polyview and Gimp allow for this, just in different places. In Polyview, right click on the image, move to color balance and you’ll see the options. To choose the white point, make that selection and move the pointer to the “whitest” spot in the image. Do the same for black point. Or, choose Auto Contrast, Auto Color Balance, and Auto Level. At first you’ll be happy letting the machine do that for you, later you will not. In “The Gimp”, I select the same by choosing Tools, Color Tools, Levels. It is much more powerful than Polyview, but you can get lost playing with the options. Usually simply setting white and black point, and not messing with the sliders, is sufficient.

4. Color Balance. Depending on your camera and lighting (and monitor, too), you can wind up with all sorts of funky colors in your image. The goal should be to return that image to as near as natural as possible. There is often way too much blue or red in an image. Polyview does a decent job of “auto color balance”, Gimp allows you to do it manually, I find that using the Tools, Color Tools, Curves is amazingly powerful, and you can modify the color curves for the whole picture, or in any of the three major colors.

5. Brightness/Contrast. These two are usually grouped together as they depend on each other but present greatly different results. I find that since I have been using The Gimp, by the time I’m done with the above 4 items I see no improvements by messing with brightness/contrast, but with other applications this can have a major effect. You can almost make up for lack of lighting but if you go too far you’ll produce a washed out image. A slight adjustment to contrast can have major impact on your image, and can take it from what it really looks like to what you wish it looked like.

A note about this – it can be tempting to alter your image in ways that make it appear better than the work really is. You CAN learn to remove sanding scratches, tear out, poor finish quality and remove flat spots that you didn’t see when the work was on the lathe.
What is the point? If the goal is to communicate your work, this serves to cheat you of valid critique and input that would provide the opportunity to improve your work. If we are being honest with ourselves and our woodturning friends, this kind of improvement is best left alone. In discussion with other turners, I have learned that several employ these techniques to remove hotspots from the lighting on their work, most people seem to think this is acceptable.

6. Sharpness. All image editing programs employ some sort of scheme (many allow you to choose the algorithms) that will improve image clarity. This is a very subjective feature. Most applications have a slider that also allows you to preview the changes. Polyview lacks such a slider and adjusts in a preset increment. The Gimp is much more powerful in this arena. It is very easy to overdo this and wind up with an image that looks fake, but some measure of sharpness increase is usually beneficial. The sharpness feature in Polyview is a drawback, in my opinion.

That is about all I do to my images. It takes just a minute or so once I decide which image to work with. You will see some people who put images inside of images to show profile views, or bottom detail. That can be done with Polyview and Gimp, too, but that is a topic for another article.

Lastly, image saving. If you are using Polyview, it is called “export image” and can be found by right clicking on the image or by choosing File, Export Image from the top menu bar. You will see choices for file type, choose JPEG. Also available will be image quality, the default is 85, but if you select “optimize quality” you will be given the opportunity to adjust quality, preview the resulting image, as well as see the size of the file it will create.

In The Gimp, it is file, save as, and follow the directions. If you click on the preview button where you have the image quality slider, you will also preview the file size. I make adjustments to just fit under the max file size of the website for which I intend the image.

That is about all I can think of for now. Like I said, I’m no expert, but I have been doing this for a long, long time, and this is what works for me. Hope it helps you some.

You can go to my webpage to see examples of some of my photo work, both good and bad. There is an obvious difference in quality in some of the photos. They were taken before John and Jamie helped me work on the parts that occur before the editing takes place. www.schwingwoodworks.com

Mike Schwing

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