Composting Part Two

There are as many ways to composite images in Photoshop as there are people who composite images. After a while, you will develop a set of tools and tricks that you will use repeatedly. For now, we’ll discuss a few more advanced compositing techniques, which will help you produce more convincing images. These may or may not be relevant to your specific application, but they should serve as a useful point of departure as you’re working on your images.

Using Filters

Filters can be very useful tools in compositing. However, it’s very easy to over-use filters: they’re among the top causes of ‘bad photoshop.’ There are a few that are useful in our specific case, however. One of the big problems you’ll run into as you try to make a digital photograph resemble an image you’ve scanned is the grain of the images. Grain means the fine texture of the image, when you’ve zoomed in very close. Mass-produced images printed on an offset press have what’s called a Moire pattern- it’s the fine distribution of dots you’ll see when zoomed in very close. Digital photos look much smoother when you zoom in. Here’s a useful process for making the grain match slightly better:

With the background layer selected, go to Filters: Blur. Select Gaussian Blur, and input a radius between 1 and 2 pixels (see what works best for your image). This should smooth out the Moire pattern, but it leaves a soft, undefined quality in the image. To fix this, go to Filters: Sharpen: Unsharp Mask. Use these settings: Amount: 20 %, Radius: 50 pixels, Threshold: 0 levels. This should get you close, and help sharpen up your softened background.

Another possible method is to add grain to your digital images. To do this, select the layer with your digital image on it. Go to Filter: Noise: Add Noise. Start with a small amount (10% or so) and use Gaussian distribution. You’ll see this adds some grit to your image. Working on both the background and foreground, you can obtain a fairly close match in grain.

More Useful Tools

There are a few more tools in the Toolbar that can help with compositing. First off, I’ll cover some more advanced settings for the Clone Stamp tool.

With the Clone Stamp tool selected, click on the Brush menu in the Control Panel at the top of the window. The two main things to play with here are the size and hardness of the brush. If you’re doing a fairly extensive cleanup process, my general principle is to start with the brush small and hard, and fully opaque (you can adjust opacity in Control Panel as well. Once you’ve gotten the rough work done, decrease the hardness of the brush, increase the size, and drop the opacity. This will allow you to smooth out and blend your copied area into the image. This process is particularly useful if you have to remove the ‘gutter’ of a book from the center of your scanned image.

Burn and Dodge Tools

The Dodge tool looks like a black version of the Zoom tool. It’s used to lighten an area of an image. It’s useful for opening up dark areas in your composited image. Use it carefully: make sure your brush is set rather soft, and start carefully, with Exposure around 50%. Notice that it lightens the area quickly: the trick is getting an even-looking lightened effect.

The Burn Tool is the opposite of the Dodge Tool- it darkens an area of your image. This is useful for adding shadows to your composited image. Use it the same way as the Dodge Tool, but again, go easy at first. It’s located under the Dodge Tool in the flyout menu.

Blur, Sharpen and Smudge

These tools work similarly to the Burn and Dodge tools, but do slightly different things: rather than darkening or lightening an area, they blur or sharpen the area slightly. This is useful for adjusting edges of a composited image, to make them clearer or softer and help blend them into the background. Again, start with Strength around 50%, and adjust as needed.

Using the Transform Tools

We briefly mentioned the Transform tools in the Edit menu, but they bear a bit more discussion. Many of them function similarly, but the Scale tool is the most commonly useful, followed by Perspective and Warp. The Perspective tool is particularly handy if you want to adjust the way your composited elements ‘sit’ in the image: it allows you to tweak how the image sits in a one-point perspective plane. Warp works by creating a grid of ‘handles’ over the image: grab any one of them to distort that portion of the image.

Use Scale and Warp carefully though: if you blow something up much larger than it originally was, you can end up with a pixilated image. Generally, to use the Transform tools, select the layer you’d like to transform, go to Edit: Transform, pick the type of transformation you’d like to use, then adjust the image using the handles which appear around it. If you don’t like your transformation, click outside your image, and a dialog box will ask whether you’d like to apply the transformation. Click ‘no’, and your image will revert to its original state. You can do the same to apply a transformation, or you can simply double-click on the image.

Capturing Digital Images and Beginning Compositing

This week, we will discuss the basics of capturing digital images on Macs, as well as beginning to composite images. You will need to shoot a few digital images to composite into your scanned images. This can be done with any digital camera that provides high-enough resolution- even your phone if you can make that work. If you don’t have access to any form of digital camera, there are digital cameras that can be checked out from the Library.

At this point, we aren’t going to get too involved with techniques for shooting digital photographs- just set your camera to Auto mode and point-and-shoot. If you have more experience with digital photography, feel free to shoot however you’d like, but don’t feel like you need special photo skills to complete the assignment. One tip: If you can set resolution on your digital camera, set it as high as possible, and shoot in TIFF mode if you can.

Once you have your images on your camera, the next trick is getting them onto your computer. The technique for doing this varies depending on the camera, but the principle remains the same: your camera functions like a remote hard drive (like your thumb drive) from which you can select and copy files to your computer.

If you have a dock, or another system for capturing images, go ahead and use it. If not, most digital cameras have a USB adapter cord. These instructions are based on using a USB cord and the Mac program Image Capture.

Here’s what you do:

1) Make sure your camera is turned off.

2) Connect the USB cord to your camera and your computer.

3) Turn on the camera.

4) Go to Macintosh HD/Applications/Image Capture, and start Image Capture

5) In the dialog box, select Download Some

6) Choose the folder you’d like to download to (Desktop is fine)

7) Select the images you’d like to download, and click Download.

Beginning Compositing

Now, I’d like to start discussing the basics of compositing images. First, we’ll go over the basic areas in the Photoshop window. They are as follows:

1) Across the top, we have the drop-down Menu area. Each of these menus has many options associated with it: generally they are global commands that affect the entire image.

2) On the left side of the screen is the Toolbar. Tools from the Toolbar are generally used to select or change only a portion of an image.

3) Underneath the Menu area is another palette: this changes based on the tool you select from the Toolbar. Generally, the items here will give you more control or allow you to access special features of the tool you’re using.

4) On the right, you will find a selection of palettes. You can customize the palettes displayed here by going to Window and selecting the palette you’d like. For now, go to Window: Layers and make sure your Layers palette is visible- we’ll be using this a lot as we start to edit.

5) In the center you will find your image. Note that there is some additional information displayed around it: the file size, the level of Zoom you are currently set to, etc.

Compositing images in Photoshop is a complex task with many subtleties. It’s a bit more of an art than a science, but we’ll cover some of the basic principles to make compositing easier. First, we’ll go over some basic adjustments and cleanup for your scanned images- it’s easier to composite if you start with a good image.

Basic Image Cleanup

After you’ve finished rotating and cropping your background image, the first thing to do is get it to print size. Don’t ever start working on a composite without knowing the print size: knowing your print size tells you how big your finished image needs to be, and can save you a lot of unnecessary work. Generally, if the image looks OK when you’re zoomed in to 100% in Photoshop, it should look OK printed, in terms of resolution and composited effects. Color is another matter entirely, but we will discuss this later.

So, go to Image: Image Size and size your image to the largest dimensions that will fit on an 8.5x 11” sheet of paper (leave yourself about a ½” margin all around), and reduce your resolution to 300 dpi. You should already have these saved as 300dpi PSD files, with 10” as the longest dimension.

If your scanned image is rotated oddly, here’s a handy trick to get it perfectly aligned. Find a line which should be horizontal. Grab the Ruler tool from the Toolbar (it lives behind the Eyedropper, in the flyout menu). Draw a line with the Ruler over the line you’d like to be horizontal. Then, go to Image: Adjustments: Rotate Canvas: Arbitrary. In the rotate menu, the number of degrees you’ll need to rotate to make your line horizontal will pop up. Hit OK. Once this is done, you’ll need to crop the image. Grab the Crop tool, make sure all your values in the menu bar are empty, and crop out any white space which shows up after rotating.

The Layers Palette

You’ll be doing a lot of work with the Layers palette as you’re starting to composite in Photoshop, so let’s take a minute to look at it. You should just have one layer at this point, labeled “Background.” Layers in Photoshop allow you to ‘stack’ images to create a finished image. Layers in the Layers palette are arranged from the top down- so the top layer in the Layers palette is the top layer in your image. If you can’t see something in your image, the arrangement of your layers is the first thing to check.

To make a new layer (with nothing on it), click on the little page of paper at the bottom of the Layers palette. You can also rename layers if you’d like. Clicking and dragging layers allows you to change the order of layers. Finally, clicking on the eye next to a layer hides its contents- so you can ‘turn off’ a layer if you don’t want to see it.

The big thing to remember with layers is that you can only edit one layer at a time. If Photoshop won’t let you edit part of an image, it’s probably because it’s not on the layer you’ve selected. This is really important, and can get confusing fast. So, make a habit of naming your layers right away- so you can click on the Astronaut layer when you want to edit the Astronaut, for example.

As a first step, go to Select: Select All, then Edit:Copy your image. Go to File: New. This will make a new document which is the same size as your image. Go ti Edit: Paste. This will place your image on a new layer in your new file. This is now your working canvas. This allows you to edit your background more easily- unless it’s copied, you can’t move it around.

General Image Corrections

1) In the Image: Adjustments menu, you will find a large number of adjustment controls for your entire image. Say you don’t like the colors, or the contrast, or would like increase the saturation- you can do all of these things here. At this point I’m more interested in familiarizing you with the options, than giving all the really technical details- play with these if you’d like. If you don’t like something, you can always hit Command-Z and undo it.

Some Useful Tools

In the Toolbar, there are several tools that are useful to know right off the bat. Always remember: if there’s a little arrow at the lower left of a tool, click and hold down on it for more tools hiding underneath it. We will discuss a few more of these tools next week.

1) The Move Tool. This is the top tool on the menu, with an arrow. You can move objects back and forth in the varied layers. Just select the layer, and click + drag, or use your keyboard arrow keys to move objects around. Remember: you can only move objects on the active layer. Select the layer with the object you’d like to move before moving it.

2) The Lasso Tools. These are great for selecting and copying an area of an image. They work slightly differently- the regular Lasso tool just lets you draw an area to select, but the Polygonal Lasso works well for outlining objects, as you can click on a series of points to outline the object. The Magnetic Lasso is good for isolating people or objects- it ‘snaps’ to edges of color variation. Use it carefully.

3) The Healing Brush tool. This looks like a band-aid. The Healing Brush eliminates small defects or spots in an image by sampling the pixels around the point you want to clean up. In order to use it, hold down Option and click a ‘good’ area of the image near the spot you’d like to clean up. This gives the Healing Brush a point to sample from. Then, click on the point you’d like to clean up, and it should be ‘healed’ away. Bear in mind that the Healing Brush doesn’t work well near edges or areas of sharp contrast, as it will bring too much of the contrasting color into the sampled area.

4) The Brush Tool. Painting or drawing with brushes doesn’t usually help too much with compositing, but for now, be aware that it’s there. Same goes for the Eraser tool. These do have applications in advanced compositing, but we will discuss that later if needed.

5) The Clone Stamp tool- this looks like a rubber stamp. The Clone Stamp tool works a lot like the Healing Brush, but think of it as an actual rubber stamp. Rather than blurring together pixels from the sample area with pixels from the healed area, the Clone Stamp just copies the area you select onto a new part of the picture. Option-Click on the sample area, then click with the Clone Stamp to replicate part of the image in a new place.

6) The Zoom Tool. This one is key. It looks like a magnifying glass. Whenever you do something by hand in compositing, zoom in to 100% to check that it looks OK. The Zoom Tool defaults to zooming in (it shows up with a plus sign in the magnifying glass): hold down Option, and it will toggle to a minus to zoom out. Just click on the area of the image you’d like to zoom in on.

Selecting and Copying Images

Now we’ll take a look at a few tricks for selecting and copying images. Generally, think of this as copying and pasting text, but just with images. The one thing to bear in mind is that images have to be of the same resolution if you want to copy and paste them together and have them end up the same size. You can certainly copy and paste a 300dpi image into a 72 dpi image, but it will end up enormous in the 72dpi image- so it’s easiest to start out with images at the same resolution. If you do end up with a scale problem, check resolution first- it’s a common cause.

To select an image, start with the Lasso tool or the Polygonal Lasso tool. Draw entirely around the object you want to copy. This should bring up a blinking marquee around the object. You could just go to Edit: Copy and then Edit: Paste the image into your background, but let’s try to make it look at bit better.

Go up to the Select menu, and then Modify Selection. This brings up a wide range of options- generally, you want to slightly feather your edges to help blend the image into your background, and there are numerous other controls you can play with to refine your edges.

Finally, if the scale of a pasted image is wrong, you can tweak it by going to Edit: Transform: Scale. This will let you perform some basic scaling on your image.

Also, note that Photoshop automatically creates a new layer whenever you paste into another image- this helps a lot as you’re building up a large composite image.

A Helpful Note:

Please, please, please, feel free to experiment with Photoshop. This is truly the best way to learn.  I will be introducing you to the set of tools I usually use to composite images in Photoshop: but there are many other ways to do it.  Always experiment and play with new features and menus: if you don’t like the result, just hit Command-Z. So, if you’re stuck, try poking around the menus or looking at different tools: come with questions, and I’ll help out.

For Next Week: Shoot and capture your digital images. Start playing around with compositing them, and bring how-to questions to class next week.

Quick Resizing How-To

1) Open a scanned image in Photoshop.

2) Go to File- Save As, and save your image as 'Cleanup.psd' or something like that. I'd like you to have the original scan, your working PSD file (make sure to select PSD from the drop-down file type menu in the save dialogue.

3) If necessary, go to Image-Image Rotation and rotate the image 90 degrees, depending on the orientation of your scan.

4) Draw a line with the ruler tool, on a line in the image you'd like to be horizontal.

5) Go up to the Image menu, then down to Image Rotation, then down to Arbitrary in the Rotate menu. This will open a small dialogue box, showing the number of degrees Photoshop needs to rotate the image in order to make your line horizontal. Click OK. This should rotate the image to make your line horizontal.

6)Go to the Crop tool in the tool menu on the left side. It looks like a black square with the lines overlapping at the corners.

7) Set the long dimension of the crop tool to 10”, and the resolution to 300dpi.

8) Drag the crop tool over your image to crop out any white areas on the sides left over from rotating the image.

9) Double-click the cropped area to make Photoshop crop the image.

10) Save your cleaned and rotated Photoshop file.

9) Now that you've saved the PSD, save a JPEG for web. With your cleaned-up PSD file open, go up to the Image menu, and select Image Size. First, make sure Resample Image is unchecked in the dialogue. Change the inch dimensions of your image to 5” on the long dimension. Hit OK.

10) Go back to Image-Image Size. This time, check the Resample box, and then change the resolution to 72 dpi. Hit OK. This will shrink your image down to web resolution.

11) Now, go to File- Save As. Name your file, and then make sure to select JPEG from the drop-down file type menu. Hit OK. A JPEG dialogue box will appear. Set the quality to 9 or 10. Hit OK. Now you have a web-resolution file ready to email to me. Do this for each of your three images. Attach all three JPEGS to an email and send to me by Wednesday the ^6th at 5pm. Thanks.

Introduction to Bitmap Images and Resolution

1) What is a bitmap?

a) Bitmap or Raster images are composed of a grid of individual pixels.

b) Each pixel has one solid, specific color

c) The Bit Depth of the image determines how many different colors any

given pixel in the image can be.

i) So, in a black and white bitmap image, any pixel can be either

           black or white- a bit depth of two.

d) In essence, bitmap images function like huge, intricate Pointilist

paintings- your eye sees the individual pixels as making up a gradient.

e) As a test, let’s take a very close look at a bitmap image. Go to the class blog, and click on the image at the top. This should bring up a window with only the image in it. Drag the image to your desktop, and then open it in Photoshop. (It’s called ResolutionDemo.jpg)

f)To see the individual pixels in this image, go to the View menu in Photoshop, then scroll down to Show, and over to Grid. Then, go to the Photoshop menu, to Preferences, then down to Guides and Grid.

g) Under Grid, select Gridlines Every 1 Pixel, and 1 Subdivision.

Hit OK.

Then, click on the Zoom tool, and zoom in to 800% or 1200% (these numbers show up on the bottom left of your image window). You’ll see individual boxes of flat color- each one of these represents one pixel in your image.

2) Resolution in Bitmap Images

a) If bitmap images are grids, resolution is determined by the number of

pixels in the grid.

b) We talk about resolution in terms of PPI (Points per Inch/Pixels per

Inch) or DPI (Dots per Inch) PPI is for on-screen images, and DPI

refers to printed images, or images we intend to print.

c) If you open an image in Photoshop, and then go to Image- Image Size,

a window will show you the size in inches and pixels of your image. The window also shows you the resolution of the image in Pixels per Inch.

d) Our test image here is 3” x 5”, at 100 DPI. If we multiply 3 inches by

100 PPI, this gives us a dimension of 300 pixels, which we see above in the Pixel Dimensions window. So, you can always determine the pixel dimensions of an image this way, by multiplying the PPI by the actual dimensions.

e) Images with higher resolution, or larger dimensions, hold more

information and take up more hard drive space.

f) The two most important numbers in terms of resolution are 72 dpi and

300 dpi. 72 dpi is the resolution of most computer monitors- so you

need at least 72 dpi at your finished size to look good on a screen. 300 dpi is print resolution- so you need at least 300 dpi at your finished size to look good printed. Because screen resolution is much lower than print resolution, an image that looks good on screen may not look good printed.

g) As an experiment, download an image off the Internet and open it in

Photoshop. Most images from the web are at 72dpi, and look good at their normal size. However, if you zoom in on the image in Photoshop, it will very quickly break apart into pixels and look ‘pixelated’. With an image at higher resolution, you can zoom in much further before it begins to break down.

3) Resizing Bitmap Images

a) The next step in understanding bitmap images is resizing an image.

b) The same ‘Image Size’ window in Photoshop not only tells you the

dimensions of your image, but also allows to you change its size.

c) Make sure you have ‘Constrain Proportions’ checked, and ‘Resample Image’ unchecked.

d) Now, change the resolution of the image to 50 dpi. The dimensions of the image in inches will double, though the pixel dimensions will not. So, as long as ‘Resample’ is unchecked, the amount of information in the image stays constant. You are simply stretching or compressing the same amount of information over a larger or smaller space. Think of it as each pixel doubling in size: you have the same total amount of pixels, but to make them cover twice the area, each one must be twice as large.

e) So, if you have an image from the Internet at 72dpi, if you make it

approximately four times smaller, it will approach print resolution of 300dpi. Conversely, you can make a print-resolution image much larger for uploading to the Internet. In either case, you are simply reconfiguring the existing image- you’re not adding or subtracting information.

f) The key concept here is that an image contains a fixed amount of

information- any changes to the amount of information require either discarding information (decreasing pixel dimensions) or adding information (increasing pixel dimensions).

h) As long as the pixel dimensions of an image stay the same, you aren’t actually changing the information in the image- you’re just distributing it differently. But, the thing you want to avoid is making the pixels so big that you can see them.  You can increase the inch dimensions of your pictures as much as you’d like- but you’ll start seeing pixels fast. It’s even easier to spot pixels in a printed image- so you need more pixels to print than for monitor viewing.

4) Using the Resample option

a) Now, let’s check the Resample box. This is a very different type of

resizing than what we were doing with Resample off.

b) With Resample, you can change the amount of information in an image,

either increasing or decreasing it. If you change the resolution field now, the dimensions of the image stay the same.

c) What you need to remember here is that you can always downsample

(make smaller). This is simply a process of ‘throwing away’ extra information. Either changing size or resolution makes the image smaller. However, you should always save your smaller image with ‘Save As’, to make a copy and preserve your original hi-res file.

c) Upsampling. Photoshop allows you to increase the size or resolution of

the file. However, you do not gain much by doing this- the amount of information is fixed, and by asking Photoshop to increase the size, you are simply making Photoshop ‘guess’ or interpolate extra pixels. This usually gives a fairly poor result, especially with low-resolution images. So, this is why printing an image from the Internet, even if you’ve upsampled it, usually gives a pixelated result.

d) So, just because Photoshop tells you that you have a 300dpi image, it may still look bad printed- because you didn’t start with a good-quality image.

Bitmap File Types

           

1) JPEG,

a) abbreviated as .jpg

b) Stands for Joint Photographic Experts Group

c) Most commonly used for web display of images

d) Compressed format- converting a file from TIFF or PSD to JPEG involves discarding information.

e) Smaller files than TIFF or PSD images

f) Poor results when printing from JPEGs- avoid this if possible

g) compatible with a wide range of graphics programs

2) TIFF

a) abbreviated as .tif

b) stands for Tagged Image File Format

c) Generally uncompressed format

d) Good for output from scanners

e) Good for printing

f) Larger file size than JPEG- poor for web use

g) Compatible with a wide range of graphics programs

3) PSD

a) abbreviated as .psd

b) Stands for Photoshop Document

c) Proprietary file type, and default for Photoshop

d) Uncompressed file format

e) Best for printing from Photoshop

f) Allows full use of all Photoshop features

g) Largest of the file types due to the amount of information Photoshop includes with the file.

Intro to Scanning- Flatbed Scanner

           

1) Set up Scanner

a) Turn on scanner

b) Start Epson Scan from the Dock

c) Open top of scanner

d) Place your image, face down, on the scanner glass.

e) Many objects can be scanned- just so long as they

1) Do not scratch the scanner glass

            2) Do not leave residue on the scanner glass

f) In Epson Scan, make sure you have ‘Reflective’ selected-

because you’re scanning an opaque object.

g) Hit Preview/Prescan at the bottom of the window

2) Set up your Scan

a) Once the scanner has generated a preview of your image,

select the area you’d like to scan (the scanner previews the entire

scanning bed initially)

b) Select resolution for your scan. If you plan on printing larger than your original image, you should scan at more than 300dpi- for example, scan at 600 dpi if you plan on doubling the size of the image.

c) Select your output format. For our purposes, select SAVE, and then select TIFF for the file format. This is an uncompressed format that can easily be converted to PSD for Photoshop use.

d) Try out enhancement options in the scanner window- especially Auto Color, which can significantly improve the color quality of your image.

e) Hit Scan. Epson Scan will ask you where to save the image, and what format you’d prefer to use- select TIFF, and pick a place to save it.

g) Find the file on your computer, and open it in Photoshop.