About measurement (Photoshop Extended)
Using the Photoshop Extended Measurement feature you can measure any area defined with the Ruler tool or with a selection tool, including irregular areas selected with the Lasso, Quick Select, or Magic Wand tools. You can also compute the height, width, area, and perimeter, or track measurements of one image or multiple images. Measurement data is recorded in the Measurement Log panel. You can customize the Measurement Log columns, sort data within columns, and export data from the log to a tab-delimited, Unicode text file.
For a video on measurement features, see www.adobe.com/go/vid0029.
Measurement scale
Setting a measurement scale sets a specified number of pixels in the image equal to a number of scale units, such as inches, millimeters, or microns. Once you’ve created a scale, you can measure areas and receive calculations and log results in the selected scale units. You can create multiple measurement scale presets, although only one scale can be used in a document at a time.
Scale markers
You can place scale markers on an image to display the measurement scale. Scale markers can appear with or without a caption displaying measurement scale units.
Set the measurement scale (Photoshop Extended)
Choose Analysis > Set Measurement Scale > Default to return to the default measurement scale, 1 pixel = 1 pixel.
Set measurement scale
- Choose File > Save to save the current measurement
scale setting with the document.
To display the scale in the Info panel, choose Panel Options from the panel menu
, and
select Measurement Scale in the Status Information area. 
To display the measurement scale at the bottom
of the document window, choose Show > Measurement Scale
from the document window menu.
Use scale markers (Photoshop Extended)
Measurement scale markers display the measurement scale used in your document. Set the measurement scale for a document before creating a scale marker. You can set the marker length in logical units, include a text caption indicating the length, and set the marker and caption color to black or white.
For a video on measurement features, see www.adobe.com/go/vid0029.
Create a scale marker
The scale marker is placed in the lower left corner of the image. The marker adds a layer group to the document, containing a text layer (if the Display Text option is selected) and a graphic layer. You can use the Move tool to move the scale marker, or the Text tool to edit the caption or change text size, font, or color.
Add or replace scale markers
You can place multiple scale markers in a document, or replace existing markers.
- Choose Analysis > Place Scale Marker.
- Click Remove or Keep.
- Enter settings for the new marker and click OK.
Performing a measurement (Photoshop Extended)
You can measure using the Photoshop selection tools, Ruler tool, or Count tool. Choose a measurement tool that matches the type of data you want to record in the Measurement Log.
Create a selection area to measure values such as height, width, perimeter, area, and pixel gray values. You can measure one selection or several selections at once.
Draw a line with the Ruler tool to measure linear distance and angle.
Use the Count tool to count items on the image, then record the number of items. See Counting objects in an image (Photoshop Extended).
Each measurement measures one or more data points. The data points you select determine the information recorded in the Measurement log. Data points correspond to the type of tool you’re measuring with. Area, perimeter, height, and width are available data points for measuring selections. Length and angle are available data points for Ruler tool measurements. You can create and save sets of data points for particular types of measurements to speed your workflow.
Measurement Data Points
- Angle
- Angle of orientation (±0‑180) of the Ruler tool.
- Area
- Area of selection in square pixels, or in calibrated units according to the current measurement scale (such as square millimeters).
- Circularity
- 4pi(area/perimeter2). A value of 1.0 indicates a perfect circle. As the value approaches 0.0, it indicates an increasingly elongated polygon. Values may not be valid for very small selections.
- Count
- Varies according to the measuring tool used. Selection tool: the number of discontiguous selection areas on the image. Count tool: the number of counted items on the image. Ruler tool: the number of Ruler lines visible (1 or 2).
- Date and Time
- Applies a date/time stamp of when the measurement occurred.
- Document
- Identifies the document (file) measured.
- Gray Value
- This is a measurement of brightness, either from 0 to 255 (for 8‑bit images), 0 to 32,768 (for 16‑bit images), or 0.0 to 10 (for 32‑bit images). For all gray value-related measurements, the image is internally converted to grayscale (equivalent to choosing Image > Mode > Grayscale) using the default grayscale profile. Then the requested calculations (mean, median, minimum, maximum) are calculated for each feature and for the summary.
- Height
- Height of the selection (max y - min y), in units according to the current measurement scale.
- Histogram
- Generates histogram data for each channel in the image (three for RGB images, four for CMYK, and so on), recording the number of pixels at each value from 0 to 255 (16‑bit or 32‑bit values are converted to 8‑bit). When you export data from the Measurement Log, the numeric histogram data is exported to a CSV (comma-separated value) file. The file is placed in its own folder at the same location where the measurement log tab-delimited text file is exported. Histogram files are assigned a unique number, starting at 0, and progressing by 1. For multiple selections measured at once, one histogram file is generated for the total selected area, plus additional histogram files for each selection.
- Integrated Density
- The sum of the values of the pixels in the selection. This is equivalent to the product of Area (in pixels) and Mean Gray Value.
- Label
- Identifies and automatically numbers each measurement as Measurement 1, Measurement 2, and so on. For multiple selections measured simultaneously, each selection is assigned an additional Feature label and number.
- Length
- Linear distance defined by the Ruler tool on the image, in units according to the current measurement scale.
- Perimeter
- The perimeter of the selection. For multiple selections measured at once, one measurement is generated for the total perimeter of all selections, plus additional measurements for each selection.
- Scale
- The measurement scale of the source document (for example, 100 px = 3 miles).
- Scale Units
- Logical units of the measurement scale.
- Scale Factor
- The number of pixels assigned to the scale unit.
- Source
- Source of the measurement: Ruler tool, Count Tool, or Selection.
- Width
- Width of the selection (max x - min x), in units according to the current measurement scale.
Create a data point preset
- Choose Analysis > Select Data Points > Custom.
- Select data points to include in the preset.
- Click Save Preset and name the preset.
- Click OK. The preset is saved and is now available from the Analysis > Select Data Points submenu.
Edit a data point preset
- Choose Analysis > Select Data Points > Custom.
- Choose the preset you want to edit from the Preset menu.
- Select or deselect data points. The Preset name changes to Custom.
- Click Save Preset. Enter the original preset name to replace the existing preset, or a new name to create a new preset.
Use the Measurement Log (Photoshop Extended)
When you measure an object, the Measurement Log panel records the measurement data. Each row in the log represents a measurement set; columns represent the data points in a measurement set.
When you measure an object, a new row appears in the Measurement Log. You can reorder columns in the log, sort data in columns, delete rows or columns, or export data from the log to a comma-delimited text file.
For a video on measurement features, see www.adobe.com/go/vid0029.
Display the Measurement Log
Do one of the following:Choose Analysis > Record Measurements.
Choose Window > Measurement Log.
Select rows in the log
Do one of the following:Click a row in the log to select it.
To select multiple contiguous rows, click the first row and drag through additional rows, or click the first row and then Shift-click the last row.
To select noncontiguous rows, click the first row and then Ctrl-click (Windows) or Command-click (Mac) additional rows.
To select all rows, click Select All.
To deselect all rows, click Select None.
Select columns in the log
Do one of the following:Click a column header.
To select contiguous columns, click a column header and drag through additional columns, or click the first column header and then Shift-click the last column header.
To select noncontiguous columns, click the first column header and then Ctrl-click (Windows) or Command-click (Mac) additional column headers.
Reorder, resize, or sort columns in the log
Do one of the following:Drag selected columns to reorder them in the log. The column position is indicated by a double black line.
To resize a column, click the column header and then drag the separator.
To sort data in a column, click the column header to change the sort order, or right-click the header and choose Sort Ascending or Sort Descending. (Rows cannot be manually reordered.)
