jpeg Picture Processing

Back in July I wrote this post about jpg artifacts and promised that I would give some tips on handling jpg (jpeg) files to avoid artifacting. Just as a quick refresher, jpg artifacts result from the over-compression of jpg files to the point that pixel information is so degraded that you start to see large groups of square pixel shapes where once many pixels existed.

JPEG files are an image file format that is "lossy". This means it is a compressed file type with some of the original file information "lost". Jpg file types were invented to display images online in the early days of the "dial-up Internet" when we all used to wait (im)patiently for files to appear in our browser windows.

The compression of a jpg file happens at the time you save the file. Initially you won't notice any apparent difference in the image, but save the file often enough, you eventually will end up with jpg artifacts, just like my cow example to the left. Yes, that was what I did in my early days as a naive Photoshop user.

So here are my easy steps to avoid jpeg artifacts.

• If you are shooting your pictures as jpeg files, shoot at the highest quality possible for your camera in the first place. Most cameras have settings for file quality under their menu settings. With memory cards as big and cheap as they are today, there's no reason to shoot at anything but the highest quality jpeg file if you are shooting in jpeg. This will mean you are starting out in the first place with the most image information possible.


• When you are ready to process your file , make your very first step that you take a conversion to a "lossless" file type such as tiff (.tif), or .psd if you use Photoshop. Depending on what image editing program you use, there may be a different file type other than psd, which is Photoshop's proprietary file type. All image editing programs probably offer tiff as an option, which is a standard/generic lossless image file. Lossless means what it says: there is no compression of the file when you save it, so no matter how many times you save the file, none of the image information is going to be lost. In fact, you may find it actually gets bigger as you process it.


• Now do all your processing such as cropping, red-eye removal, whatever you do typically, with the lossless file that you have opted for.


• When your picture is ready for prime time and sending to the printer or emailing or uploading and you want or need it to be a .jpg file once again, do one, and one only "Save as jpg". Never save that jpg file ever again.


• Treat your lossless psd or tif file as an archive file, and if you subsequently want to tweak your picture some more, come back to that file. You can save it with a different name so that you have a new version. Once again, only save it as a jpg file at the very end of your processing.

Follow these easy steps in processing jpeg pictures and you should never be visited by the horrors of jpeg artifacts. Happy photo editing!

Subscribe by email Your subscription will begin only after you activate it by responding to the email you will receive from "FeedBurner Email Subscriptions" immediately after submitting this request. If you do not see the email within the next minute, please check your spam folder.

Using Blending Layers to Remove Background in Photoshop

The other night I was playing with this old photo below of an aloe plant at the gardens at Huntington Library. I had previously created some "photo art" from it which can be seen in my plants photo gallery, and at the time had used some of Photoshop's selection tools to essentially trace around the edges of the aloe plant so I could remove the background. Believe me it was wrist-breaking, hand-numbing work, since the background is busy and not all the "contrasty" compared to the plant. In fact since it was such a hard selection to do, I just ended up cropping out a lot of the background.

So since I know more about the power of using layers and blending modes in Photoshop these days, I wanted to see how much of the background I could "knock out" by simply laying different blending modes on top of each other.

Note, you can try this with some of your own photos if you have Photoshop or Photoshop Elements.

I opened the photo in Photoshop. The first layer in Photoshop is always called "Background". I immediately made a copy of the background layer. There are several ways of doing that. I like to use the keyboard shortcut which is Ctrl+J.

The new layer will be on top of the original layer, and it will be called "Layer 1". Note that I have highlighted the blending mode which is by default "Normal" and with 100% opacity. The photo looks exactly the same as the original at this point.

You can click on the dropdown next to Normal and cycle through the blending modes. Some will make a difference, some won't. Some make the picture darker, some lighter, some funky. You can control how much of the bottom layer shows through by lowering the opacity of the top layer.

I found that the mode called "color burn", which is one of the modes that darkens an image, removed almost all of the background and changed the color of the plant to a very attractive green-blue with the purples and blues of the edge lines emphasised.

This is how it looked after doing that:

Since the whole point of the exercise was to save time and my wrist, the question remained what to do about the remainder of the background that is still visible. The simple option I chose was to blur the edges of the photo creating a "depth of field" effect where the plant is in focus, and the background out of focus. To make the background disappear even more, when I took the image back to Photoshop Lightroom, I created a dark "vignette" around the edges using Lightroom's "post crop" vignette slider. Now almost all of the background was invisible and what remains adds to the overall artistic value of the photo.

The outcome, completed from start to finish in no more than 5 minutes and without a sore wrist can can be viewed in the plant photo gallery.



Below you can watch a video of some of my photos of plants.

---

Subscribe by email Your subscription will begin only after you activate it by responding to the email you will receive from "FeedBurner Email Subscriptions" immediately after submitting this request. If you do not see the email within the next minute, please check your spam folder.

Study of a Agave at the Hungtington Gardens #1

This first study of an agave comes from my recent visit to the Huntington Library botanical gardens. You can see the original photo from which I created this and the other two versions in the following posts by scrolling down to the bottom of this post.

In creating this image you'll see that I first of all cropped out a lot of the distracting background so as to focus just on the agave.

I then selected the remaining background and darkened it. I found that the new Quick Selection Tool that comes with Photoshop CS3 worked perfectly in this case since there was a nicely defined border along the edge of the agave; the tool was able to find this edge easily.

I saved off the selection of the agave(Select>Save Selection) in case I needed to work with the selection again and also for what I was going to do in the following images. I wanted to essentially make the remaining pieces of background between the agave "leaves" black, but if I were to just simply fill those areas with black it could look unnatural, so first of all I actually blurred these areas using Lens Blur and then filled them with black and lowered the opacity down to something like 80%. This way these parts of the photo don't just look like they were cut out and blend into the background.

I did some adjustments to levels and layers as I always do, and then I made a copy of the merged layers and in this case changed its blending mode to Luminosity, also adjusting the opacity and fill levels a little. Essentially they are the steps I used in the "digital darkroom" in creating this photo.


The original photo of the agave.

Agave Study #2

Agave Study #3

Hydrangea Globe

And now for something quite different! No, it's not a pizza! To get the full effect, you need to click on the image to view the larger image.

Making a globe shape in Photoshop is actually pretty easy. These are the steps:

• Go to Filter > Distort > Polar Coordinates and click Polar to Rectangular
• Go to Image > Rotate Canvas > Flip Vertical
• Go to Filter > Polar Coodinates and this time choose Rectangular to Polar