ver. 2.0 Color correction software for digital images User s manual - Windows OS Color balance your images automatically - experience the difference! A must-have for all digital photographers!
What does QPcolosoft 501 do for you? No camera knows how to capture colors in a perfect way. Since the color temperature of incoming light differs, reflected light from a given subject also differs. Furthermore, most digital cameras register colors through separation filters that are not perfect. The best way to figure out how colors in the subject are affected by incoming light and by camera properties, is to take a photograph of a known color sample and compare the colors captured by the camera with the real colors of the sample. When you know in what way your camera is changing the colors, you can also figure out how to reverse all captured colors, in order to make them resemble the real colors in the subject. This is what QPcolorsoft does for you. Place the color sample QPcard 201 in the subject and take an image. Use QPcolorsoft 501 to compare the captured colors with the real colors and to create a correction profile for all images taken under the same lighting conditions. About color Color is created in the brain of a human being. Different wavelengths of visible light are detected by the red-, green- and blue-sensitive cones in the retina of a human eye. In a digital camera the cones are replaced by silicon elements filtered for red, green and blue light. Visible light has wavelengths between 400 and 700 nm. Color is defined by the wavelength of the light. Color is dependant on the reflecting and absorbing qualities of a surface, and by the characteristic of the incoming light. One of the qualities of our brain is the ability to adapt to different circumstances. If the light is very warm, our brain will adapt it to normal light. If the light is very cold and blue, our brain will adapt it to normal light again. We can walk from a deep blue shadow on a sunny day, to a sunlit area, and to tungsten light indoors without noticing the difference in color temperatures. Digital cameras are trying to behave in a similar way by using automatic white balance. The problem The color reproduction qualities of a digital camera are almost never perfect. White balance, filter characteristics and software behaviour, all influence the color interpretation of a digital camera. When you first look at a digitally captured color image on a screen 1
it is rarely perfect. You need to balance neutral grey and correct some of the colors. In many cases the color shift differs from highlight to shadow areas of the image. Furthermore, it is impossible for a camera to know if the yellow light reflected from a subject, is warm tungsten light from in a white surface or white light reflected from a yellow surface. The solution There are no digital short cuts here. There is only one way to determine how incoming light and camera imperfections affect the color rendition of the subject. Take a photograph of a familiar color sample and compare the result with a reference sample! In order to correct the colors our software creates a correction profile. The card QPcard 201 is a 142 x 40 mm cardboard card with 30 color, grey, white and black patches. Four of these, in the corners, are the same grey tone in order to help the software check the uniformity of the incoming light. There are five grey shades between black and white, and 20 different color patches. The 27 color patches on the card are not printed with offset technique or on photographic color paper. When offset printing or photo paper is used, all colors are mixtures between the three basic colors cyan, magenta and yellow. In QPcard 201 all 27 colors are mixed separately from pigments in order to get the highest accuracy in color properties. On the back of the card there is a strip of adhesive protected by a plastic sheet. Peel off the plastic and the card can easily be mounted on almost any surface. Image of the card The most important step towards getting perfect colors in the image is to make the calibration image of QPcard 201. It is this image the QPcolorsoft 501 software is using to determine the difference between the real colors and the colors your camera is rendering in the specific light. It is very important to set a fixed white balance on your camera. Never use auto white balance when you are intending to create a color correction profile with QPcolorsoft 501. It is also very important to take an image of the card in the correct light. Make sure that the light on the card is even. Avoid light reflections on the card. Try to take the image with the card in a parallel position to the sensor or film plane of the camera. 2
Don t over or under expose the card. If the white and/or black patch on the card appears too light or too dark in the image, QPcolorsoft will warn you. If there is too big a difference in light between the four corners of the card, likewise QPcolorsoft will warn you. The software QPcolorsoft 501 is an easy to use stand-alone product. The user interface is intuitive with functions similar to Adobe Photoshop. You open an image with QPcard, choose the reference rendition you prefer, mark the card and press a button for profile creation and another button for color correction of the image. In QPcolorsoft 501 there is also a batch processing capability. The Toolbar 1) Open a document 2) Save a document 3) Move an image within the frame 4) Marking tool for a QPcard 5) Zoom in 6) Zoom out 7) 180 turn of mark outline 8) Create a color correction profile 9) Convert the image with chosen profile 10) Undo conversion of the image Preferences In the Preference dialogue box (under File in the menu) you can choose a default folder for your saved color correction profiles. You can choose whether or not you want to adjust your monitor with default monitor profile. Images can be saved in TIFF or JPEG format. If you want to save an image compressed in JPEG format, you can choose between different quality levels. A low level will give you a small image file in poor quality. High quality, or 100% will give you a file that is less compressed and thus larger in size. In Preferences you can choose default level of JPEG quality. When you save your images you can always choose another level of compression. 3
Menu - File Under File in the menu you can Open, Close, Save or Save As images. You can choose Batch Processing and set Preferences. The images latest opened can be reached from the File menu. Menu - Image The File-menu Here you can create a profile and convert the image. And you can undo the conversion. Under Image you can deselect the outline around the card. You can also rotate the outline 180 here (or by pressing the F key). You can also rotate the whole image 90 clockwise or counter clockwise. Menu - Profile The Image-menu Profile in the menu handles color correction profiles in the Profile Bar. You can Add a saved profile, Save a created profile or remove profiles from the Profile Bar. The Profile-menu Menu - View Under View in the menu you can choose whether or not you want the Tool Bar, Profile Bar and Status Bar to be visible on your monitor. Here you can also choose how you want the image displayed on the monitor. Real Size, Fit on Screen and different zoom options can be chosen from this menu. The View-menu 4
Menu - Window The Window-menu From the Window menu you can choose how to show your images on the monitor and also reach all open images instantly. Menu - Help The Help-menu From the Help menu you can open the manual in PDF format and go straight to QPcards homepage on Internet. How to use QPcolorsoft 501 1) Start QPcolorsoft 501. 2) Open an image including QPcard 201 by using Ctrl+O, or by clicking the folder symbol in the toolbar, or by using the drop-down menu File and choosing Open. 3) Choose a suitable reference from the menu Reference Neutral The color patches of QPcard 201 were measured with a spectrophotometer. Sinar From a photograph of the card taken with a professional digital Sinar camera. Velvia From a photograph of the card taken with Velvia film and scanned with an Imacon professional scanner. 4) Use the zoom tool by pressing the key Z or by clicking the zoom symbol in the toolbar. Zoom the card until it almost fills the frame. Use the mouse marker and mouse button to cover the card. You can also zoom by pressing Ctrl and +. Make sure you can see all corners of the card. If you want to zoom out, just press Ctrl and click the mouse button, or press Ctrl and -. 5) Now activate the Mark tool by pressing M or by clicking on the square symbol in the toolbar. 5
6) Mark three adjacent corners of the card. Now adjust the outline pattern over the color patches by moving the white handles in the corners until the white outline squares are covering the patches. If the card is oriented in the opposite way, simply click the two rounded arrows in the tool bar. 7) Create a color correction profile by pressing Ctrl+Enter or by clicking the profile symbol in the toolbar. Choose a suitable folder and save the profile by giving it a name. The generated profile will work for all images taken in the same light with same fixed white balance on the camera. 8) Convert the image using the selected profile by clicking the Convert icon in the toolbar. All RGB values in the image will be changed. 9) Save the converted image by pressing Ctrl+S or by clicking the diskette symbol in the toolbar. If you do not want to replace the unconverted image with the converted, choose Save as and give the image file a new name. 10) Batch process several images by choosing Batch from the file menu. Choose Add and browse to the folder you wish and mark all images you want to process. Choose the profile you prefer by pressing Add for Profile and browsing to the profile folder you wish. Choose the correct profile and press Open. Choose destination folder for the converted images. Create correction profile for digital images scanned from film This is a procedure similar to the one with images shot with a digital camera. Take an image of QPcard 201 in the light you want to use for a series of images. Scan all images with the same scanner setting. No automatic color correction in the scanner software! Open the image including QPcard 101 in QPcolorsoft 501. Create a color correction 6
profile and save it. Now open all the other images taken in the same light in the batch mode of QPcolorsoft 501. Choose the correct profile and process all images. This operation will neutralize the color effect of a specific film brand. Create a profile for a specific light If you find yourself coming back to the same photographic light time after time, you can create a specific color correction profile for that light, save the profile and use it many times. Set the white balance of the camera to the fixed position you think is most accurate for the light. Remember the setting. Take an image of QPcard 201 in the light, and create a color correction profile using QPcolorsoft 501. Give the profile a name resembling the lighting situation and/or the white balance setting, and save it in your profile folder. Use the profile for batch processing all images taken in the same light. Caution 1! When working with QPcolorsoft 501, never use auto white balance setting, since this setting may cause colors to change from image to image in the same light. Always set white balance in your digital camera in the pre-set mode you think will suit the photographic situation best. The closer you are to correct colors from the beginning, the better the likelihood for perfectly corrected colors with QPcolorsoft 501. Caution 2! Always work with a copy of the original image in QPcolorsoft 501. Always store the original image file from the camera in a safe place. Creating a color correction profile doesn t affect the image, but converting the image with a profile changes all RGB values in the image. Caution 3! Be careful when you take the calibration image of QPcard 201. The light falling on the card must be the same light as in the main subject you are intending to photograph. 7
The card must be flat and facing the camera in an almost 90 angle to the optical axis. The light must be even on the card The card must not be over exposed The card must not be under exposed The card must be in focus. The card should not be too small in the image. Make a close-up without casting a shadow on the card. The card must be clean and straight. Hint: QPcards are inexpensive. Replace your card often for best color correction results. The color balance in the image of the card should not be too far from correct. It is not possible to correct a 24 bit RGB image that is too blue or too red since sufficient color information is missing. 8
Color working space Since RGB (Red, Green and Blue) numbers in a digital color image are unit less and device dependant (the real color of a specific RGB number varies from device to device) the RGB numbers only indicates the values in parts of 256 in each color. In order to make RGB numbers device independent, we need to define them with a unit. The unit for RGB in a color image is called working space or ICC profile. The color working space QPcolorsoft is defining RGB with is AdobeRGB 1998. All images exported from QPcolorsoft are defined in AdobeRGB 1998. Visit www.qpcard.com On QPcard s Internet homepage on Internet you will find updates of QPcolorsoft 501, more sample images, answers to frequently asked questions, and other useful information. Visit www.qpcard.com often for the latest information about correct color! 9