Panoramas and the Info Palette By: Martin Kesselman 5/25/09 Any time you have a color you would like to copy exactly, use the info palette. When cropping to achieve a particular size, it is useful to use the width and height information in the info palette. When creating a panorama from a number of images it may be necessary to blend the image colors of different frames together. It could be useful to know exactly what the colors are and have a way to make each image the same matching color. All of the above provide a good reason to have some knowledge of the info palette. See a discussion of this palette at the end of this article. This article will discuss the procedure of creating a panorama and some methods to blend images together to provide a more seamless rendition. Panoramas: The technique is straight forward and with Photoshop s panorama capability, is relatively painless. To do it manually provides you with a more in-depth understanding of the complexity of the operations performed by Photoshop and an ability to manually provide tweaking, if necessary, manually after Photoshop has done its best. Taking the images: A panorama will be a blending of two or more images to capture an aspect ratio that does not fit your film/sensor aspect ratio. Some digital cameras have a panorama feature that will tell you where the next image should go and how much overlap to provide to help you merge the images together. If you are shooting a horizontal panorama, it is useful to use manual focus, manual exposure settings and a tripod to permit a level pan. All images should be shot with the same focus and focal length and exposure. This is not always available to you and you end up with problems later merging the images. To achieve a better panoramic aspect ratio you might want to use your camera in portrait position (height larger than width) and overlap about 30% for each image. This could result in more images to merge, but will provide a resultant more pleasant aspect ratio. Bring the images to be merged into Photoshop. Go to file>automate>photomerge. In the Use window choose open files. Press OK.
The image merged here contains five separate images. Assure the Keep As Layers box is checked. This will allow each image to be brought into Photoshop on a separate layer for additional merging enhancements. Click OK.
The layers palette has each image on a separate layer for further adjustment. Careful observation of the way the images merged shows problems with the sky rendition. A blow-up of the first three images merged together show that Photoshop did a fine job placing the images together but the exposures appear slightly different. This is correctable using the levels adjustment on just certain layers/images without affecting the other layers. To do this, select a layer to adjust and highlight it by clicking on the layer, to the right of the layers name. This will highlight the layer so it is the active layer. Lets choose the third image (the one with the gold dome) as the exposure we want to match. Therefore, highlighting the adjacent image and focusing our attention on the sky we will match the sky exposure. Select add a levels adjustment layer by holding the alt key while clicking the add adjustment layer icon (black and white cookie) and selecting levels.
The New Layer dialog window opens. Click the check box Use previous layer to create clipping mask. Click OK. The Levels adjustment layer will open above the active layer and it will be indented with a small arrow pointing down to the layer below. This indicates that it is going to adjust only the layer below. You will adjust the mid-tones slider to achieve a blending of the sky colors and brightness. You can see here that the images appear better blended. Do the same with the other images. Blending them the best you can. Then crop the results to complete the panorama image.
Here you can see the extra levels layers added to blend the sky in each case except for CRW7643. which was the one we were using as a reference. Other adjustments can be done to improve contrast, color balance, etc. The concept of directing the adjustment to the layer below using the check box in the new adjustment layer dialog window is a powerful feature. This technique can be applied to the curves adjustment layer where you can select the red, green and blue layers separately and locate the intensities of each color at a specific point to match the color accurately.
Sampling a Point on an Image First we need to learn how to sample a point on an Image to obtain color data. The tool for this is the eyedropper tool. You will also have to have the Info Palette open on your workspace to see the data numbers. Open the info palette, if it is not already open, by pressing f8 or using window>info. Wherever you place your cursor in the image area the color information will be displayed. See end of this article for more details on the info palette. 1- To place a sample point; activate the eyedropper tool by selecting it or press the I key on the keyboard. 2- Set the sample size to 3x3 average. 3- Move the eyedropper to a desired location on your image and hold the shift key down while you left click your mouse. This will place a sample point on your image. It will not print but will stay with your file if saved as a PSD. 4- To remove the sample point, hold the shift key and the alt key down, the eyedropper icon will change to a scissor when you place it over the sample point. Left click the mouse to cut the sample point out. When a sample has been taken it will appear along with the sample number at the bottom part of the info palette. A total of four samples can be displayed. 1- Write down the red (R), green (G), and blue (B) values for transfer later to another image where you would like the same color. I have turned off all of the layers except the reference layer to demonstrate the process. The sample point was selected near the edge to be close to the blending line of interest (the image has been expanded to see the edge and sky area easier). You can see the values displayed in the info palette.
Now turn on the adjacent image layer and turn off the reference image layer. The sample point is in the same place but has different values. We will change these values using a curves adjustment layer affecting only this layer. Add a curves adjustment layer that uses the previous layer as a clipping mask as done earlier. 1- With the layer you want to adjust active hold the alt key while left clicking the add a new adjustment layer icon (black and white cookie), and select curves. 2- The new Layer window opens. Check the use previous layer to create clipping mask check box and click OK. 3- A curves adjustment layer is created above your active layer. Move your cursor over your sample point. It becomes an eyedropper icon. Hold the shift key and the ctl key down while clicking the left mouse button to set a point on the color channels. a. Hint: to accurately locate the sample point press and release the cap-lock key. When you place the cursor on the image it will change to a target just like the sample point. When the two are over each other the icon and sample point disappear. b. Be certain after you have completed the remaining steps to un-set the caplock by press and releasing it. The cap-lock set can cause peculiar results when you are trying to use tools. Be certain it is off for most all of your Photoshop efforts. 4- A circle will briefly appear on the curve and go away when you release the mouse key. This is because the curves channel is set to RGB. Change the channel to red or green or blue and you will see that there is a black point selection on each of these channels. 5- With the red channel selected highlight the output window numbers and type in the value recorded earlier for red. 6- With the green channel selected highlight the output window numbers and type in the value recorded earlier for green. 7- With the blue channel selected highlight the output window numbers and type in the value recorded earlier for blue. 8- Click OK. 9- Turn on both layers and observe the colors have been made identical.
The Info Palette: The info palette is a useful palette that will help you analyze your images and provides you with information about selected pixels to improve color balance and copy color from one place to another. To show the Info palette on your workspace; press f8 or use window>info.
The eyedropper cursor is over a generally gray area ( note; 3x3 sample size is selected). The info palette shows the color to contain R=157, G=157, B=157. These being the same number, indicate a neutral value slightly brighter than mid-tone (128). Ignore the data to the left. It reflects the cursor located someplace else. Click the top right drop down menu arrow to display options. These items can be selected to suit your needs. The following has been taken from Photoshop Help: To use the Info palette The Info palette displays file information about an image and also provides feedback about the color values as you move a tool pointer over an image. Make sure the Info palette is visible in your work area if you want to view information while dragging in the image. (Optional) Do one of the following if you need to display the Info palette: Click the Info palette tab if it s docked with other palettes. Choose Window > Info. File information about the image is displayed at the bottom of the Info palette. You can change the information displayed by clicking the triangle in the upper right corner of the palette and choosing Palette Options from the palette menu. (Optional, Photoshop) Set the options for the information you want displayed in the Info Palette by doing any of the following: Choose Palette Options from the Info palette menu and specify options in the Info Palette Options dialog box. Click an eyedropper icon and choose display options from the pop up menu. You can also use the pop up menu to specify whether the Info palette displays 8 bit, 16 bit, or 32 bit values. Click the cursor coordinates icon and choose a unit of measurement.
Select a tool. Move the pointer in the image, or drag in the image to use the tool. The following information may appear, depending on which tool you re using: Displays the numeric values for the color beneath the pointer. Displays the x and y coordinates of the pointer. Displays the width (W) and height (H) of a marquee or shape as you drag, or the width and height of an active selection. About the Info palette The Info palette shows the color values beneath the pointer and, depending on the tool in use, gives other useful information. In Photoshop, the Info palette also displays a hint on using the selected tool, gives document status information, and can display 8-bit, 16-bit, or 32-bit values. (Photoshop) The Info palette displays the following information: Depending on the option you specify, the Info palette displays 8-bit, 16-bit, or 32-bit values. When displaying CMYK values, the Info palette displays an exclamation point next to the CMYK values if the color beneath the pointer or color sampler is out of the printable CMYK color gamut. When a marquee tool is being used, the Info palette displays the x and y coordinates of the pointer position and the width (W) and height (H) of the marquee as you drag. When the Crop tool or Zoom tool is being used, the Info palette displays the width (W) and height (H) of the marquee as you drag. The palette also shows the angle of rotation of the crop marquee. When the Line tool, the Pen tool, or Gradient tool is being used, or when a selection is being moved, the Info palette displays the x and y coordinates of your starting position, the change in X (DX), the change in Y (DY), the angle (A), and the distance (D) as you drag. When a two-dimensional transformation command is being used, the Info palette displays the percentage change in width (W) and height (H), the angle of rotation (A), and the angle of horizontal skew (H) or vertical skew (V). When any color adjustment dialog box (for example, Curves) is being used, the Info palette displays before-and-after color values for the pixels beneath the pointer and beneath color samplers. If the Show Tool Hints option is enabled, you see hints for using the tool selected in the toolbox. Depending on the options selected, the Info palette displays status information, such as document size, document profile, document dimensions, scratch sizes, efficiency, timing, and current tool. (ImageReady) The Info palette displays the following information: The RGB numeric values of the color beneath the pointer