https://renewip515.weebly.com/samsung-led-tv-series-45-user-manual.html. Viii The Gimp User’s Manual Table Of Contents. Grayscale And Line Art 194 Complementary Or Inverted Colors 194. Chapter 14: Pre-press And Color In Gimp.197. What Is Pre-press? 198 Printing From Gimp 198 Preparing For The Press 201 At The Print Shop 203 Scanning Using A UNIX Or Linux System 205 Calibration 206. Check out the FEATURES OF THE GNU Image Manipulation Program (GIMP) SOFTWARE NEW 2019 Version Software Download! GIMP can also be scripted in Perl, Python (Python-Fu), or Tcl, using interpreters external to GIMP. Easily make black and white coloring pages from any photo. GIMP User Manual Included! GIMP comes with a built-in help system. There are a few ways to do this, but the technique described Separating an Object From it's Background section of the GIMP user manual works well in most cases. Once you have the area that you want to change it's color in a separate layer, you can just work with that layer, without affecting other white parts of the image.
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2013-08-13 18:39:11 UTC (over 6 years ago)permalink
B&W negatives.
Apologies if this is all too obvious (except for me?), but is there a way to convert a black & white negative (scanned) to a positive, in Gimp (now, alas, using Windows 8, for the moment). I thought there was (perhaps it was distant memories of my Photoshop days, using Mac? :))?
Thanks in advance for any pointers.
Henry
2013-08-13 22:27:10 UTC (over 6 years ago)permalink
B&W negatives.
On 13-08-13 02:39 PM, Henry W. Peters wrote: At&t user manuals downloads.
Apologies if this is all too obvious (except for me?), but is there a way toconvert a black & white negative (scanned) to a positive, in Gimp
Right click the image -> Colors -> Invert
2013-08-14 00:02:38 UTC (over 6 years ago)permalink
B&W negatives.
On 8/13/2013 6:27 PM, Kevin Cozens wrote:
On 13-08-13 02:39 PM, Henry W. Peters wrote:
Apologies if this is all too obvious (except for me?), but is there a way to
convert a black & white negative (scanned) to a positive, in Gimp
Right click the image -> Colors -> Invert
Thanks Kevin, live & learn!
Henry
17C H A P T E RImage Menu: Colors The Image menu offers some of the most useful image manipulating functions in Gimp. In this chapter, we’re going to discuss what you can do with Colors in the Image menu.
Image Menu: ColorsCOLORS The first part of the Image|Colors menu deals with how image pixels are mapped to different RGB values; the second part deals with color correction; and the third part contains useful filters for auto-correction of scanned photos. Remember that you’re likely to get much better results adjusting scanned images in a professional image manipulation program like Gimp, than in the scanner pro- gram.EQUALIZE Right-click|Image|Colors|Equalize is often used to correct over- exposed or underexposed photos. Equalize finds the darkest and lightest pixels in the image and sets the darkest value to black and the lightest to white. Intermediate colors are then translated to the corresponding histogram values on the new scale. This action adjusts the image pixel colors to a wider scale or spectrum. The resulting image is usually harder and much clearer, with more saturation and con- trast, but often with less fine detail. Figure 17.1 Comparing dark and light images before and after Equalize has been invokedDark input Output after EqualizeLight input Output after Equalize274 The Gimp User’s Manual
INVERT Chapter 17 Tip: Equalize can be used to find “hidden” colors in old, fading photos, because colors are also equalized. For example, if there is a weak shade of green somewhere in a seemingly solid blue area, Equalize will find it and strengthen it, while the blue color will lose intensity. Sometimes, this results in colors looking a bit unnatural after equaliza- tion. You might have to correct the image using color correction tools like Color Balance. For adjusting old photos, it is sometimes better to use other commands such as right-click|Image|Colors|Auto-Stretch HSV, Auto- Stretch Contrast and Normalize. Try all of them and see which one is most suitable for your picture. Right-click|Image|Colors|Invert creates a color negative of your image (or a positive of your negative). Free 10 22 user manual from ruger. Invert is very useful if you have a slide scanner, because then you never have to worry about expensive developing. You need only develop the negative film, and then you can do your own developing with your computer. Figure 17.2 Invert is shown on the right side The calculations are quite simple: The inverted RGB value of a pixel is 255 minus the former channel value. Read more about inverted or complementary colors in “Complementary Or Inverted Colors” on page 194.The Gimp User’s Manual 275
Image Menu: ColorsPOSTERIZE Right-click|Image|Colors|Posterize is a way of creating an “indexed” image, in which the colors are derived not from the image, but from the number of possible combinations the three RGB channels can produce. The avail- able colors depend on what you set as Posterize Levels in the Posterize dia- log. Figure 17.3 Posterize is shown at the bottom-left sideTHRESHOLD For a grayscale image, it’s easy. Posterize Levels 0, 1 and 2 produce the minimum of possible colors: black and white only. For each level, you get one more gray- scale. Posterize Levels 4 equals four shades of gray, Posterize Levels 16 equals 16 shades of gray, etc. For an RGB image, Posterize Levels 4 equals four different shades in each color channel. So Posterize Levels 4 equals 4x4x4, or 64 colors. Those 64 colors were chosen by dividing the color value of each channel into even multiples of 4, so only the values 0, 85, 170 and 255 are used. As those colors may not be similar to the original colors in the image, only a few of them will be used in the image. A posterized image will be a lot less represen- tative, but (perhaps) will be more “artistic” than an indexed image, where the cho- sen colors are taken from the image. The right-click|Image|Colors|Threshold dialog displays a brightness histogram of the image. Each spike in the histogram represents a value ranging from 0 to 255. The longer the spike, the more pixels that have that partic- ular value. In the preview window, you can see where those pixels are situated in the image.276 The Gimp User’s Manual
Chapter 17Figure 17.4 The Threshold dialogClicking on a single spike displays only the pixels with that particular value. If youdrag from one spike to another, Gimp will display all pixels with a threshold rangefrom the first value to the second.You can use the Threshold command to make a line art (black and white)image. Threshold is also an excellent tool for selecting by value. If you copy yourimage to an alpha channel, and use Threshold on the alpha channel (see “Chan-nels And Duotones” starting on page 351 for more information on alpha channels)you can, for example, select all pixels dark enough to represent a certain shape anduse that to make a selection. Figure 17.5 Line art created with ThresholdThe Gimp User’s Manual 277
Image Menu: ColorsCOLOR BALANCE Right-click|Image|Colors|Color Balance allows you to adjust the color levels in your image. Color Balance changes colors in the image, but not as drastically as Hue-Saturation. Use Color Balance when you want to make subtle changes in color. Figure 17.6 The Color Balance dialog In the Color Balance dialog, you’ll find three slide bars ranging from the three RGB colors to their complementary colors (CMY). As you know if you read “Image Menu: Colors” starting on page 273, the sum of two complementary col- ors is neutral gray. You can consider your current pixels “neutral” (or zero) and any change you apply will move the pixel color either toward Red or Cyan, Green or Magenta, Blue or Yellow. Moving all three sliders towards the CMY (subtractive) colors will darken your image, while moving them toward the RGB (additive) colors will lighten the image. The dialog includes three radio buttons: Shadows, Midtones and Highlights, which respectively correspond to the darkest pixels, the medium pixels or the brightest pixels. Click on the button corresponding to the pixels you want to affect. If you click on the Preserve Luminosity checkbox, the brightness value of your image doesn’t change. By default this option is unchecked, because the image’s colors can become very unnatural-looking if you insist on keeping the original values while changing the color balance.278 The Gimp User’s Manual
Chapter 17Figure 17.7 Outputfrom Color Balance isshown at the bottom-leftsideBRIGHTNESS-CONTRAST Right-click|Image|Colors|Brightness-Contrast is easy to under- stand. The zero values represent the current values of your image. Figure 17.8 The Brightness- Contrast dialog From that “neutral” point, you can raise or lower the amount of Contrast and Brightness.The Gimp User’s Manual 279
Image Menu: Colors Figure 17.9 Image corrected on the right with Brightness-ContrastHUE-SATURATION The right-click|Image|Colors|Hue-Saturation dialog lets you adjust Hue, Saturation and Lightness (or Value). You should understand that this option is entirely based on the HSV color model, as explained in “HSV” on page 191. Figure 17.10 The Hue-Saturation dialog. You can adjust the sliders by dragging on them with your mouse, by typing values into the boxes or using the left and right arrow keys on your keyboard. When you change Hue with the Master checkbox checked, all pixels in the image or selection will change color according to how many degrees you have turned the HSV color circle. If you just want to change part of the spectrum, you280 The Gimp User’s Manual
Gimp User Manual Black And White Background
Chapter 17can choose any one of the color radio buttons (Red, Yellow, Green, Cyan,Blue, or Magenta).Remember, HSV is the color model being used here (not RGB). Because it isHSV, checking the Yellow button and changing its value won’t necessarilychange the yellow parts in your image.Figure 17.11 The huecircleIn HSV, the yellow swatch starts at 100% pure yellow on the HSV color circle(no orange shade whatsoever is allowed) and continues toward green. Everythingin the yellow to green slice is affected by changes to hue, saturation or value. Yel-low pixels get the color you see in the swatch, and greenish pixels get the nextswatch color (clockwise), and so on, as they get greener.So, if you want to affect yellow pixels that are slightly to the red side, choose thered swatch instead. The red swatch changes all color between pure red and yel-low. Because of this, Hue-Saturation is unsuitable for certain images. For mostimages, it’s very useful indeed, but if you have trouble with it, try ColormapRotation in the right-click|Filters|Colors menu instead (there arevery few things you can’t achieve with that filter).Figure 17.12 The truckhas had its color changed byHue-Saturation (right side)The Gimp User’s Manual 281
Image Menu: ColorsCURVES The right-click|Image|Colors|Curves tool is an advanced instru- ment for changing the color, contrast and brightness of an image, or a certain color/brightness range in an image. Figure 17.13 The right side of the image has been adjusted with Curves Simply put, the image’s RGB values (and possible alpha values) are repre- sented by curves, and you can change a curve any way you like by dragging at different parts of it. When you first open the Curves dialog, you’ll see a straight, linear curve. This curve is called Value and represents the values of all three RGB channels of the current image. Value here does not mean value as in HSV. Curves is based entirely on RGB values. Remember the Threshold command? When you looked at your image with Threshold, you could choose an area from spike A to spike B, and that area rep- resented pixels of intensity A ranging to intensity B. Curves works the same way. The leftmost segment of the curve represents the darkest pixels in the image, and the rightmost segment represents the lightest pix- els. The vertical grayscale gradient to the left of the curve displays what brightness value the curve follows.282 The Gimp User’s Manual
Chapter 17Figure 17.14 The Curves dialogCHANGING BRIGHTNESS AND CONTRASTTo understand Curves better, open an image and try it out. Try dragging the mid-dle of the curve up and down. While you are doing this, take a look at the gradientbelow the curve.The gradient and the preview image show that dragging down makes your imagedarker, and dragging up makes it lighter. The middle of the curve representspixels with midvalues. By creating a soft curve in this fashion, you havechanged the general brightness values a lot, but you have only changed highlightsand shadows a little, so you have less contrast now.Reset the Value curve, and drag the right part of the curve (representing high-lights) up, and the left part (representing shadows) down, until your curve isshaped like an S. With this procedure you have made bright parts lighter and darkparts darker; you’ve increased the contrast without changing the brightness inthe image.On the lower horizontal gradient, you’ll see that the balance of dark and light hasbeen changed and you can also see where on the scale it happened and how much.If you are in a color channel (select Red, Green or Blue from the ModifyCurves for Channel pull-down menu), this procedure will make pixels moreor less green, red, or blue.In a color channel, dark means pixels with little of that color, and light means pix-els with a lot of that color in them. If you are changing alpha, it works the sameway. Dark means a low alpha value, or very transparent. Light means a high alphavalue, or very opaque.The Gimp User’s Manual 283
Image Menu: Colors ADJUSTING CURVES You may have noticed that there is a dot at each end of the curve. Drag at one of the dots. You’ll find that the line created to the left or right of the dot is perfectly straight. In practice, this means that dragging the left dot constrains a range of dark pixels to the same value, whereas dragging the right dot constrains a range of light pixels to the same value. How large this range or interval will be depends on the horizontal length of the line. The darkness or lightness of the pixels depends on where you put the dot on the vertical scale. Click on different points on the curve. Each click produces another dot, and you can move each dot independently of the others. You can move them up, down or along the curve. These dots are like Bezier anchor points, but without handles. This means that by moving a dot, you’ll produce a little curve between the two nearest dots. This way you can easily pick a suitable pixel range, and only change the values within that range. To remove dots, drag them toward one of the end dots. You can remove all of the dots except one, but if you only have one dot, your curve will be flat. A flat curve causes all values to be the same. If all of the values are the same, your image will turn gray and disappear (or, for example, if you’re in the red channel, all pixels will get the same red value). The option Curve Type: Free lets you create or modify your curve with a pen- cil, which offers unlimited possibilities of fine-tuning colors or values. The Smooth option will produce a smoother version of the same curve. Experiment with Curves to learn more. Unwanted Side Effects Because the value is based on RGB, you can sometimes produce an unwanted change in color when you only wanted to change the pixel brightness. This effect happens when you try to make extreme changes, like lightening a very dark object without disturbing the other colors in the image. If you try to do this, you’ll invert the color, and you’ll just end up with something red if the object was green. Instead of using Curves to produce this effect, you should isolate the object in a selection and use right-click|Filters|Colors|Value Invert. This filter works in HSV, and inverts Value without changing Hue or Saturation.LEVELS Right-click|Image|Colors|Levels is another way of manipulating RGB properties. Levels is an excellent tool for creating highlights or shadow areas, which enhance 3-D effects in your image. Levels is also useful for adding emphasis to dark or bright areas in the image. Whereas Curves allows you to manipulate pixels within defined ranges, Levels affect the entire range of pixels. You normally use Levels for changing the gen- eral balance between bright and dark parts in the image or selection, and Curves when you only want to affect certain color or value ranges.284 The Gimp User’s Manual
Chapter 17USING LEVELS IN ALL CHANNELSWhen you open the Levels dialog, you’ll see a histogram of your image’sValue (all RGB channels) or of the Red, Green, Blue or Alpha channel if youswitch channels in the Modify Levels for Channel drop-down menu.Figure 17.15 The LevelsInput LevelsThe histogram shows the input levels of the image. For example, the histogramshown in Figure 17.15 shows an image that has no black or really dark areas. Theblack arrow below the histogram represents the minimum value (0) in the RGBchannels, the white arrow represents the maximum value (255) and the grayarrow represents the mid value (127 on the RGB scale). The area between theblack-and-white arrows always defines a pixel value range from 0 to 255.If you’re working with a grayscale image and you drag the white or blackarrows, every pixel to the left of the black arrow turns black, and everything to theright of the white arrow turns white. Each spike between the black-and-whitearrows represent pixels of different shades of gray, and the pixels with mid value(127) are in the spike above the gray arrow. You can change the balance of lightand dark pixels by moving the gray arrow.Move the white-and-black arrows toward the center. The result will be more con-trast and less detail, because the gray transitional range between black and whiteis narrowing. Move the gray arrow. Moving it to the left adjusts the brightness bal-ance so that more and more of the gray pixels end up in the range between mediumgray and white (they get brighter), and vice versa.If you’re working with an RGB color image, the pixels to the left of the blackarrow will turn into either black or one of the additive primary colors (red,The Gimp User’s Manual 285
Image Menu: Colors green or blue). Pixels to the right of the white arrow will turn into either white or one of the subtractive primary colors (cyan, magenta or yellow). For an image with low contrast, if you drag the black arrow to the start of the his- togram (the first spike), the white arrow to the end of it (the last spike) and put the gray arrow in the middle, you have pretty much done the same thing that right- click|Image|Colors|Equalize does, i.e., broadened the spectrum of the image. Output Levels The Output Levels gradient controls the overall brightness value. As you drag the black or white arrows on the Output Levels gradient, the new values define the brightest/darkest value in the image. As a result, the entire image becomes darker or lighter. The output is always more dull than before, because there will be less contrast when the value for the darkest and/or brightest pixel is being moved towards the gray mid values. Figure 17.16 Contrast has been lowered on the right side, using Levels ADJUSTING LEVELS IN A SINGLE CHANNEL When you switch from Value to a Color channel in the Modify Levels for Channel drop-down menu, remember that we’re no longer talking about dark and light. We’re now discussing the quantities of color in the image. RGB Output And Input Levels In the Output Levels gradient, dark means low values of the color in question, and light indicates that pixels have a lot of that color in them. The Output Levels gradient controls the value range that pixels can use for a cer- tain color. In other words, if you modify the levels for the Green channel by setting the Output Levels to between 100 and 120, all pixels with a little green in them (even if it’s a very low value) will shift to a new green value of at least 100. No pixel’s green value can be greater than 120. Dragging the white arrow to the left286 The Gimp User’s Manual
Change Black To White Gimp
Chapter 17causes the image to have less green (i.e., more red). The opposite is true when youdrag the black arrow to the right.The result of moving the Input Levels arrows in a color channel isn’t as obviousas with Value. The result depends on how much of the color is in the image, andin what range most of the color is found.Levels And Alpha ChannelsThe alpha channel works the same way as RGB: Dark means low alpha (or trans-parent) and white is high alpha (fully opaque).Modify Levels for the alpha channel on feathered or otherwise semi-transparentselections or layers, i.e., on areas with great variation in alpha values. Examples ofthis are selections created from an alpha mask channel or layers where youhave applied a Layer mask.EXAMPLE: MAKING CARVED TEXT WITH LEVELSTo help you understand what you can do with Levels, work through this example: 1. Create a new image with a white background. With the command File| New, choose Fill Type White (you can just leave the Fill Type at Background if the background color in the toolbox is set to white). 2. Create a white layer in this image. Use the command right-click| Layers|Layers & Channels to open the Layers & Channels dialog. Click on the New Layer button. In the New Layer Options dialog, click on Layer Fill Type White and click OK. 3. Click on the Background in the Layer & Channels dialog, so you’re working in the background layer. Choose the Text tool and write a few (black, not gray or colored) letters on the white background. In this example we used white text on a black oval. You may have to click “off” the eye icon on the new layer so that you can see the background. With the letters still selected, apply some right-click|Filters|Blur|Gaussian Blur. The more blur you apply, the more bevel and softness you’ll get in the bumpmap image you’ll create next.The Gimp User’s Manual Figure 17.17 White letters before and after Gaussian blur 287
Layers And Floating Selections Keep Trans. protects the boundaries of opaque shapes in a transparent layer. It also makes it very easy to change opaque shapes’ colors, because you never have to worry about painting outside of their edges. If you want to use a filter on a layer, you normally won’t want to have this option checked, because if Keep Trans. is checked, the filter will only affect the interior of opaque objects in the transparent layer. Naming You can rename a layer by double-clicking on the layer’s old name. The Edit Layer Attributes dialog will allow you to type in a new name. Figure 20.4 The Edit Layer Attributes dialog THE LAYER TOOLBAR BUTTONS New Layer Creates a new layer, as described in the paragraph “New Layer” on page 317. Raise Layer And Lower Layer These commands (and the corresponding buttons on the Layers & Channels dialog) move the active layer to a higher or lower position in the layer hierarchy. You can only raise or lower a layer one step at a time. The background layer can’t be raised, unless you rename it or apply Add Alpha Channel (see “Add Alpha Channel” on page 325). Duplicate Layer Makes a copy of the active layer, and places it immediately above the original. Delete Layer Deletes the active layer. Anchor Layer Anchor Layer is used to merge floating selections with a layer (the layer that was active before you placed the float). If you don’t know what a floating selection is, read “Floating Selections” on page 331.320 The Gimp User’s Manual
Chapter 20Usually, all you need to do is click in a floating selection to make it stick to a layer.Sometimes, the Move tool needs to be active for this to work (for example, whenyou are trying to anchor a floating text string). However, the Anchor Layercommand always works and is quick, especially if you use the shortcut key(Ctrl+h, unless you’ve changed your hotkeys).THE LAYER DIALOG MENUIf you right-click on a layer’s bar, the Layer Dialog menu will appear. Thefirst five commands (and Anchor Layer) on the Layer Dialog Menu have alreadybeen discussed in “The Layer Toolbar Buttons” on page 320, and the more com-plex options, such as Layer Mask and alpha commands, will be discussed in thenext section.Scale LayerShrinks or enlarges the layer and its contents, to measurements that you specify.Resize LayerChanges the size of the layer, but not its contents. If the contents of the layer arelarger than the new layer size, the image or selection will be cropped to fit the newlayer size. You can use X Offset and/or Y Offset to place the original layer ina particular spot inside a larger resized layer.Figure 20.5 The Resize Layer dialogThe Gimp User’s Manual 321
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