Make adjustments to underexposed images
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
In prepress design, there are often some images of underexposed originals. If they are put into the design, they will not only affect the effect of the entire design layout, but also undermine the designer's creative taste. The magic of Photoshop is that you can use some of the means it provides to easily adjust the underexposed pictures to restore their original appearance.
1. Scan an underexposed image and enter it into your computer
The photos taken with the digital camera are entered into the computer and opened in Photoshop. Scanning a picture to set the scanning resolution is not sloppy at all, as it directly controls the re-imaging quality. Generally adhere to the following principles:
1.1 When the scanned image is used for color inkjet printing, the resolution of the color inkjet printer and the scaling factor of the image should be considered. The resolution represented by a color inkjet printer refers to the output precision of various colors. It is not a true resolution. Dividing the resolution identified by the printer by the color number of the printer is its effective precision. If the resolution is 720dpiOr a 1400dpi four-color printer with effective resolutions of 180dpi and 350dpi.
If the output is printed according to the original size, the scanning resolution should be equal to the effective accuracy of the printer. If the image needs to be scaled to print output, scan resolution = zoom factor output size ÷ original image size × printer effective accuracy.
1.2 When the scanned image is used for printing, the number of printed lines and the image scaling factor should be considered at this time. The number of printing lines is how many mesh units can be printed per inch in the printing machine, the unit is l/inlpi; the scaling factor = output size ÷ original size. If the printing is equal, the scanning resolution = the number of printing lines × 2. For example, the number of printed lines in newspapers is generally 85lpi, and the average color print is 150lpi. The beautiful album is 300lpi, then the corresponding resolutions are: 175dpi, 300dpi, 600dpi . If the image is scaled, the scanning resolution = number of printing lines × 2 × scaling factor output size ÷ original size. In determining the problem of printed network cable, don't just pursue the larger number of network cables. The larger the number of network cables, the more abundant the presentation image level and details, but the prepress design must fully consider what kind of printing is used. The paper, for example, printed on the newsprint with a network cable of 175l, not only does not get a beautiful effect, but will cause the image to be blurred, which is counterproductive. The author's personal experience is that when using newsprint or offset paper offset printing, the printing network cable is 80-100l; therefore, the resolution should be 160dpi~200dpi. Between the color printing of 210g or less coated paper, the printing network cable can reach 175l, and the resolution should be 200dpi~300dpi. Between the use of 210g or more high-grade copper plate paper color printing, the network cable can be set higher. In short, too high a resolution setting will result in wasted time, too low to affect the printing effect.
1.3 When the scanned image is displayed on the screen, in general, if the display is equal, the scan resolution is set to 72dpi; If the display is zoomed, its resolution is set to: 72dpi × zoom factor.
Opened in Photoshop, because the backlight is used for shooting, the subject is underexposed, so the person's face appears too dark image file.
2. Execute the Image/Copy command to copy the currently operated image as a separate copy. In the pop-up dialog box, click the "OK" button to confirm and copy the image.
3. Execute the "Image" / "Mode" / "Grayscale" command to convert the copied image mode from RGB to grayscale format.
4. Execute the "Filter" / "Blur" / "Gaussian Blur" command, set the blur radius to the appropriate value between 3 and 6 according to the size of the image, and then determine the blur radius set in this example to 4.0, the image will be Make the appropriate blur.
5. Now switch the current operation file to the original image file and execute the "Select" / "Load Selection" command to bring up the "Load Selection" dialog box. Set the copied image file name in "Document"; select "Grayscale" in "Channel"; then select "Invert"; select "New Selection" in the "Operation" option. After the settings are completed, press “OK” to confirm, and the selection will be loaded into the image. At the same time, it can be clearly seen that the selection at this time is just the underexposed part of the image.
6. Convert the current operation file to the copied image file, press the "Ctrl+W" key combination to close the image file. At this time, you will be prompted whether to save or not. Select "No".
7. Execute the "Edit" / "Fill" command, pop-up "Fill" dialog box, from which to set the relevant options. Select "50% Gray" in "Use"; "Color Dodge" in "Mode"; set to 100% in "Opacity".
8. When the setup is complete, click OK to confirm and fill the selection of the image. Press the "Ctrl+D" key combination to cancel the selection.
Through the operation of the above eight steps, it is easy to adjust a photo that is not effective enough to be substantially satisfactory. By adjusting, the brightness of the underexposed portion of the original image is improved, and the details in the shadow range are fully expressed without affecting the brightness of other parts of the image.