Digital Image Editing (1 Viewer)

[fmethorst]

I thought I would start a thread on the techniques I use to add backgrounds and visual effects to some of my pictures. I'm learning as I go so hopefully this thread will develop as I do. I also encourage others to share their digital editing techniques.

Before I get started I thought I'd bring up the subject of photo manipulation since I think in some cases this carries a negative connotation. How often do we hear "Oh that's been Photoshopped" used to dismiss a picture outright? While I can certainly appreciate the ethical concerns if this technology is applied inappropriately (i.e. journalistic or historical revisionism) I do believe that it has a place as an art form. Certainly when combined with another art form, the diorama, I think photographic results can be enhanced in ways not possible with the techniques applied to static dioramas. I'm sure there are purists out there who would consider any digital alteration an abomination but I have come to appreciate the power of the technology while attempting to retain the integrity of the subject matter.

While I had experimented in the past with extracting elements of pictures and placing them in different scenes I didn't really see the potential until I was working on a background for my steppe dioramas. I found a few nice pictures on the Internet that I figured I would download, resize to a size that I could place behind my diorama and then print them off in sections of 8 1/2 x 11 paper. When I experimented with this the results were OK but far from stellar. Then it struck me, if I'm using an image editor to resize an internet image for printing why don't I just digitally place the background behind the diorama. This had several advantages. For one it eliminated the color printer from the equation which solved problems with image quality and in my case seams to join all the segments together. I also found the digital image retained its original brightness much better than a printed image placed behind the subject. It solved the depth of field issue of having to try to get both foreground and background elements in focus. It gave me complete control over perspective. With a static background image, only pictures taken at one specific angle will look right with any given background. Using a digital background allows the horizon to be moved up and down to match the angle of the photography. Lastly the background can be shifted both right and left and resized to suit the requirements of the main subject. The only downside was how to get the digital background to blend into the forground scene in a manner that didn't draw attention to itself. That said, blending in a static background picture can be challenging too. Once I started using digital backgrounds in my pictures it wasn't long before I started experimenting with other effects such as dust and smoke. It also proved very useful in hiding figure bases.

While I realize that digital image editing is of no value for creating a static diorama that will be displayed for people to view live, I feel it offers an opportunity for those of us that like to create temporary scenes for the sole purpose of taking pictures and then putting all the elements away again.

Here is our first project, adding a background to this picture.

The frame antenna and vehicle corner markers are going to make this challenging.

 

[fmethorst]

Information about the camera:
Camera: Nikon D300s
Lens: Nikor AF-S DX 18-200mm f/3.5-5.6G ED VR
Resolution: 12.3 megapixel
Mode: Manual aperture, manual shutter, auto focus
Mounted on a tripod, Shutter released in mirror up mode via remote cable release.

Information about the picture:
Aperture: f/32
Exposure: 1.6 seconds
ISO: 400
Focal Length: 200mm

Information about the software:
Operating System: Microsoft Windows 7
Photo Editor: Adobe Photoshop Elements 8.0

While this camera will give better results than any point and shoot is capable of I am often surprised just how good those little cameras can perform so don't be discouraged if you don't have a digital SLR. The important things to remember are lighting and stability. While flash photography can produce some nice pictures it doesn't look natural and loses all the depth possible with light coming from a different position than the camera so my recomendation for lighting is to use a source other than the camera's flash. Natural light is excellent so if you can take advantage of a window then great. My preference is color corrected photographic lights but these can be a few dollars so don't be afraid to try what you have on hand. Try combining light from a window with an artificial light source. If possible the camera should be mounted on a tripod and either a remote cable release or a timer should be employed. The slightest camera movement at this magnification can blur your image.

Lets talk a little about digital pictures. A digital picture is made up of lots of tiny little squares called pixels (see picture below). Each of these squares is assigned a combination of red green and blue color shades. 24-bit truecolor uses 8 bits to represent red, 8 bits to represent blue and 8 bits to represent green. 2 to the 8th = 256 levels of each of these three colors can therefore be combined to give a total of 16,777,216 mixed colors (256 × 256 × 256). The dimensions of a picture in pixels is determined by the resolution of the digital image sensor in the camera. For instance, my camera can produce 12.3 megapixel images which are 4288 pixels wide x 2848 pixels high (4288 x 2848 = 12,212,224 pixels). This means that every picture I take has over 12 million little squares that make up the image and every one of those little squares can be one of over 16.7 million colors. Good thing we have computers to deal with all this number crunching. When dealing with pictures that you view on your computer the only measurement that matters is the dimension in pixels. The dimension in inches or centimeters is only relevant when you want to print a picture so I won't discuss it further here. Understanding image dimensions in pixels is helpful for more than digital editing. It allows you to size your pictures exactly the way you want so they look best on a computer monitor.

In Windows you can view information about a picture by right clicking on the file and selecting properties

If you select the "Details" tab the information we are interested is available

In this picture I have zoomed in on the license plate of the Sd.Kfz.232 pictured above. You can see the individual squares (pixels) that make up the image.

 

[fmethorst]

First of all we need a picture to work with. When taking pictures of your diorama don't scrimp, take lots of pictures from lots of different positions and angles. If your light source is portable move it around the subject as well and take more pictures. Pros don't try to setup and take that one perfect picture and neither should you. This is the age of the digital camera so, unlike film, there is no cost involved in taking pictures that will ultimitely be thrown away.

Here is a folder containing pictures I took of the Sd.Kfz.232 for both my review and Stalingrad picture threads. Note how many I took backlit for the sunset picture. This was because I was looking for a good combination of frontal ambient lighting and back glare.

Next we need a background image to work with. In this case I want a steppe background with a nice sky. I used Google to find a variety of appropriate pictures. One thing to note is that if an image you find online is too small it will be difficult to resize to work with your picture without losing too much resolution. In other words it will look all blocky and pixelated. I look for images that are 1000 pixels wide or bigger. Depending on the background you may be able to use an image down to 800 pixels wide but the bottom line is the bigger the image you can find the better. You can find out the dimensions of a picture in your internet browser by right clicking and selecting properties.

I keep a folder for backgrounds so that I can reuse them in the future.

Lets take a closer look at the picture I found online. Note how near the bottom of the image you can start to see the individual blades of grass. This implies that the camera is close to grass in the bottom of the picture. Since we want to use this picture as a background we can't use the bottom portion behind our foreground material because it will look strange.

So what I do is crop the picture and remove the closer foreground grass and just leave the grass further away out to the horizon.

 

[fmethorst]

We are now ready to extract those elements of my picture that represent the foreground of our final composition. In the case of this picture that repsents the Sdf.Kfz.232 and the terrain mat it is sitting on. Extracting really means removing those elements of the image we don't want. This works best if the part you are trying to remove is a solid color that is different than any of the foreground elements. You can see in the case of this picture we want to remove the wall behind the terrain mat. This is the same way blue/green screens work in the movie industry.

In PSE the "Magic Extractor" can be found under the image menu.

The "Magic Extractor" will open and look like this. Down the left side of the tool are a number of buttons. The top two are the foreground and background airbrushes. This is what you use to identify what is foreground (to be retained) and what is background (to be removed). By default two colors are assigned to foreground (red) and background (blue) elements. Down the right side of the tool are the "OK", "Reset" and "Preview" buttons. Next there is a "Tool Options" section. The only thing we are going to use here is the Brush Size box. We can ignore all the remaining settings down the right side.

The first thing we should do is press top left button to select the foreground airbrush. Next we should enter 100 (pixels) into the brush size box on the right which is the maximum size. Start by "painting" major foreground elements making sure you keep away from fine details and edges.

Keep painting the foreground until everything except the edges and fine detail are red. Your coverage doesn't need to be 100%.

When this is complete select the background airbrush and do the same process for the background.

When you have completed this stage your image will look something like this. Everything identified with red (foreground) will be retained and everything identified with blue will be removed (background). Note that the software doesn't require 100% coverage.

 

[fmethorst]

So much for the easy part. Now we have to highlight the details such as the vehicle corner markers and antenna so that they are retained in the final image. As it is if we were to press "Preview" or "OK" now a lot of the finer details would be removed from the image.

To do the detail work we need to do two things, zoom in and change our brush size. To zoom in press the magnifying glass button on the left side of the tool and click on the area of the image you want to zoom on. To zoom out hold the "Alt" key at the same time you click. This reverses the zoom. We're going to work left to right so the first thing I'm going to tackle is the right front vehicle corner marker. I set my brush size from 100 pixels down to 10 pixels and select the foreground airbrush. Note how the white ball on the end of the corner marker is quite close to the background wall color. This makes it difficult for the software to differenciate between foreground and background. In cases like this you need to ensure you paint right up to the edge of the foreground item.

Next we highlight the remainder of the marker with the 10 pixel brush. If you have trouble staying in the lines feel free to reduce the brush size to something smaller. When there is good contrast between foreground and background you DO NOT need to hilight to the edge. In fact you don't want to because the software will do a better job with straight lines than you can.

Work your way up the piece painting the nooks and crannies as you go. Click on the little hand button on the left and then click and drag your picture to move around when you're zoomed in.

In the next picture you can see how I don't hilight right to the edge but I do hilight each detail.

Now we start the antenna. In order for the software to remove the background elements properly we need to ensure we mark all the areas inside the antenna that are background with the background (blue) airbrush.Size the airbrush appropriately for the item you're painting.

Continue to work your way across the foreground elements until you reach the right side of the picture. Our picture now looks like this:

 

[fmethorst]

We're now ready to press the "Preview" button on the right side. The software will digitally remove the areas we've identified as background with the blue airbrush and leave those areas we have identified as foreground with the red airbrush. The areas that are removed and replaced with a checkerboard pattern that represents a clear area. In other words, if we layer this image on top of another image you will be able to see through this image to the image below in all the areas that you see checkerboard.

The next step is to zoom in and examine how well the software did.

In this case the software has done a fantastic job. If it turns out that the software removed a part of the foreground element you want to keep you can re-add it to your picture by selecting the fourth button down on the left "Add to selection Tool" and painting over the area that you want restored. There is also a tool to remove from selection but I wouldn't bother with that as you can remove is much easier in PSE later on.

When you are sure all of the foreground elements have been retained press OK to switch back to PSE proper. The first thing to do is save the picture.

You will have to save the picture as a PSD (Photoshop Document) format to support the fact that the image is currently a layer with clear sections.

 

[fmethorst]

If you have a mouse with a scroll wheel check the following. Click on the Edit menu and select Preferences and General.

Ensure Zoom with Scroll Wheel is ticked and press OK. With this option ticked you can use the scroll wheel on the mouse to zoom in and out of the pictures which makes this task far easier.

Now that we have the image back in Photoshop Elements proper select the Eraser tool and note the settings we have chosen. For instance I've chosen a brush size of 20 pixels. In this picture I have zoomed into the right vehicle corner marker. Notice how not all of the background has been removed around the white ball.

Carefully erase the remaining background by clicking and dragging your eraser around the subject. If you make a mistake press the Ctrl and Z key to undo you last change. You can undo multiple changes by continuing to press Ctrl Z. In the following image we have cleaned up the excess background around the corner marker.

In the following picture notice how the background hasn't been removed from the area indicated by the arrow.

A couple of clicks with the 20 pixel brush and the center is cleaned up.

To finish this area we need to change our brush to 5 pixels and finally 2 pixels to get right into the corners. Thats right we're using a 2 pixel brush on an picture that has over 12 million pixels.

The antenna is another area that needs some additional cleanup

This is what it looks like after the cleanup

 

[fmethorst]

The finished foreground image

The next step is to bring the various layers into play and resize the foreground and background to work together. Lets start by choosing a size for the final image, 4000 pixels wide. Select Resize Image Size from the Image menu.

The original size. Ensure "Constrain Proportions" is ticked. This forces the vertical size to automatically resize when you change the width.

Change the width to the size you have selected for your final image (4000 pixels in this sample)

Next we bring in our background image and resize it to match the foreground.

 

[fmethorst]

Now we need a large background layer to work on so we select new blank File from the File menu.

We want the background layer to be larger than our foreground and background elements.

I'm goiing to select 6000 pixels wide by 6000 pixels high. I'm also going to change the Background Contents to White.

We now have the three image elements necessary to complete this picture

Double click on the background image and press Ctrl A (to select all) and press Ctrl C (to Copy)

Double click the white background image you created earlier. Press Ctrl V (to paste). Select the Move tool (see arrow)

 

[fmethorst]

Double click the foreground image and press Ctrl A (to select all) and Ctrl C (to copy)

Double click the white background again and press Ctrl V (to paste) the foreground on top of the other two layers (see arrows)

With the Move tool selected click on the foreground image and drag it into position.

You need to eyeball the perspective. In this case when I drag the foreground image high enough for the perspective to look right some of the foreground elements cover too much of the background.

Select the Eraser tool again with an appropriate brush size (50 pixels in our case)

Notice how you can erase the foreground layer.

Here we've erased as much as necessary from the right side of the image.

We do a similar treatment to the left side.

If you click and drag on the pixel rulers you can pull a guide line down to help ensure everything lines up.

 

[fmethorst]

Now we need to flatten the image. This means merging all the layers. We can do this by right clicking on the layers (see arrow) and selecting flatten image

The layers are now gone so there is no more moving any of the elements around. Don't forget you can undo using Ctrl Z.

At this point we should save a copy of the picture in the JPEG format. Click on the File Menu and select Save As... Select a descriptive name and under the Format drop down list ensure JPEG (*.JPG,*.JPEG,*.JPE) is selected.

Next we're going to clean up the edge of the foreground and background image using the Clone Stamp tool (see arrow). We've selected a 50 pixel brush size.

The way to use this tool is to press and hold the Alt key and left click on an area you want to clone and then drag in the direction of where you want to copy to. Let go of the Alt key and start to paint area you want to clean up.

It's not too difficult to blend foreground and background

We need to do the same thing on the left side of the image.

If you are fussy there is still a little of the original wall background visible around the right vehicle corner marker. The Clone Stamp tool can be used to clean this up by cloning nearby background right up to the foreground subject. Notice I have changed the brush size to 20 pixels.

The picture is now almost complete

 

[fmethorst]

We now have to crop the image from the large white background (6000 x 6000 pixels). Select the Crop tool (see arrow)

Note: If we were going to add any smoke or dust effects we would do that prior to this final crop.

Drag a box around your final composition. You don't necessarily have to include all of the picture. For instance if we want less sky in the final composition this is the opportunity to cut a bit of the sky off. In this case I'm going to include the whole thing. Once the crop is selected click the check mark (see arrow)

The next step is to save the image again. This is the final 4000 pixel wide high res version of the image.

Once you have saved the composition we are going to make a smaller web friendly version (1000 pixels wide). Select Resize Image Size from the File Menu.

The original size.

The new size

If you zoom in on the picture now you will notice how the resolution has been drastically reduced. Compare this picture with the one of the same area we took earlier. Note the pixelation.

Voila, the finished web friendly composition.

We need to save this new reduced image with a different file name than our hi-res version Click on the File Menu and select Save As... Select a descriptive name (different than the one used when saving the 4000 pixel version) and under the Format drop down list ensure JPEG (*.JPG,*.JPEG,*.JPE) is selected. This low-res version is the one you will share on the web. The original hi-res version is for you to enjoy.

 

[Wraith]

Frank,

That has got to be one of the most detailed and well explained 'how-to' ever published. Even a complete technophobe like myself can understand it.
Brilliant. Great end photo and great explaination. Thanks for taking the time to share your trade secrets.

Cheers
Simon

 

[The Lt.]

Joining Simon Frank in his compliments an I'm sure you'll find those who have the softwear and are not very well versed in it's useage will soon be using your help hand big time.

 

[fmethorst]

Thanks guys.

I'd had a couple inquiries regarding the process so rather than try to explain individually it seemed to make sense to post here.

The thing I enjoy is that it really allows the creative juices to flow. Here is one I did a while ago.

 

[fmethorst]

The next part of this tutorial will deal with smoke and dust.

Here is the foreground image we are going to start with. It features Honour Bounds Winter Panther and their new Panzer Crew set. We are going to add a winter sky and some smoke effects.

 

[fmethorst]

Before we start on the Panther picture lets discuss the basics.

I opened a digital sky background I have to use for this demo. The first thing I did was size the background so it would work with the pictures my camera produces. This means that the sky you are looking at is 4000 pixels wide (to learn how to resize see the beginning of this thread). I have highlighted the relevant tools within PSE with red arrows. On the top left we have the lasso tool. On the bottom left we have the color picker and on the right we have our old friend the layers window.

Here is a close up of the color picker. There ae two squares, one overlaid over the other. The square on top represents the foreground color and the one on the bottom represents the background color. Selecting appropriate colors for your smoke/dust effect is critical to achieving satisfactory results. Later in this demo I will discuss colors further including how to sample elements of your picture to ensure colors are appropriate. For this demo I have arbitrarly selected two darker shades of of grey. I have found the best results are achieved by using the same color for both foreground and background color and keeping the shades relatively close.

If you click on either the foreground or background square in the color picker you will see a selection box like this. The arrow pointing to the left highlights the color I have selected. The arrow pointing to the right highlights the hue selector bar. You can click anywhere along this bar to select the base hue and then fine tune the color in the main square. I have chosen blue as the base hue. The actual colors I want are right along the left side of the picker square. This is where the greys are found. For this demo I simply selected two different shades along the far left side of the picker square.

Now that we have our colors selected lets render some smoke. Select the lasso tool from the button bar.

Draw a shape on your picture by clicking the left mouse button and dragging you mouse. Make sure you continue holding the button until you get back to your starting point or the software will arbitrarly finish the shape for you with a straight line.

From the Filter menu select Render\Clouds

Hmm...well the center of our shape looks promising but we have a problem, the sharp edge. Smoke is diffuse so this edge simply won't do. Let's go back a step. If you remember from the previous tutorial you can undo any change you make by pressing the Ctrl-Z keys (you can also find undo in the Edit menu). If we undo one step we should still be left with our shape but the rendered "Cloud" should be removed.

This time before redering the "Cloud" select Feather from the Select menu.

You will be prompted with this box. This is basically asking how much feathering to add in pixels. If the shape you drew is 800 pixels across and you select 200 pixels of feathering then the center 400 pixels will be solid "Cloud" like the picture two above and a 200 pixel band will be gradually feathered towards the edge. You really have to experiment to when selecting the amount of feathering as it is dependant on the source picture and size of your smoke/dust object etc. This will be discussed in more detail later.

Now go back to the Filter menu and select Render Clouds

That's getting better

Frank

 

[fmethorst]

So far we have created this smoke effect

If you look at the right side of the image you may have noticed that the feathering has created a problem along the right side of the picture. Since it wasn't possible to draw the smoke outline outside of the picture there is a 200 pixel straight band of feathering along the right side of the picture. This looks a little strange.

So how do we fix it? Well, we're going to turn to layers yet again. We're going to create a virtual canvas that will allow us to paint outside the constraints of the picture. Start by going to the File Menu and selecting New\Blank File...

Change the dimensions of this new background layer to be quite a bit larger than the original picture. My picture is 4000 pixels wide so I've made this new background 8000 x 8000 pixels. In the Background Contents drop down box select White. This is the color of the background.

Double click the original picture in the open picture box. This will bring it to the front. Press Ctrl-A (Select All) and then Ctrl-C (Copy)

Double click the white background in the open picture box to bring it to the front.

Press Ctrl-V (Paste) to paste the original picture on top of the white background. Notice how in the layers window on the right side of PSE the white background is the background layer and the original picture is layer 1.

Right click on the background layer and select Flatten Image.

This combines all layers into a single layer. The picture now has a large white border that we can overpaint on.

So lets try this again. Select the colors from the color picker, select the Lasso Tool and draw an outline for the smoke like we did the first time. This time; however, carry on the shape past the right edge of the orginal picture.

 

[fmethorst]

Select Feather.. from the Select Menu

I'm going to use the 200 pixel feather again

Select Render\Clouds from the Filter Menu

That's a better result

Now all that remains is cropping the picture back to the original size. Select the Crop Tool from the tool bar. Draw a box around the original picture by clicking and holding the mouse button and dragging the mouse from one corner to the other. If it lookks OK press the little tick mark at the bottom of your selection. If it's not quite right press the cancel beside the tick mark and start over.

Here is the result

Here are a few samples where I have varied the shades of grey.

 

[fmethorst]

So lets take what we've learned above and apply it to that Panther picture.

Using the techniques described in the tutorial on the 232 I am adding a winter background to the foreground I have extracted from the original picture. It should be noted that I had to decrease the blue level of the background and increase the blue level of the foreground to get the snow to match between background and foreground.

Once the foreground and background images are alligned properly all the layers are flattened into a single picture.

Using the techniques described in the smoke tutorial I draw a smoke shape rising to the right from the engine compartment. I have drawn a red arrow to a shortcut method of achieving the feather effect. If you type in a feather value here you can skip the feathering step described in the smoke tutorial. I have selected 200 pixels for this image.

After picking two dark greys from the color picker I select Render\Clouds from the Filter Menu.

Next I draw a narrow smoke cloud coming from the turret hatch which combines with the main cloud coming from the engine compartment.

I'd like a little more smoke near the turret so I draw a small smoke cloud near the turret. Note that if the amount of feathering you have selected is greater than the size of the shape you have created you will see a pop-up box like this. Press OK and render the cloud as you would normally. In this case the smoke will be transluscent all the way across the cloud. This is useful when adding a little smoke that you don't want to overpower a picture.

The next step is to crop the image

The last thing to be done is blend the foreground and background snow.

The final result