Working With Images
From Scribus Documentation Project
To create an image frame, click the Image Frame icon on the toolbar, or from the main menu: Insert > Insert Image Frame, click on the toolbar icon for image frames or use keyboard: I. Click-drag-let up on the document to create your frame. A new, empty frame will show a black cross from the diagonals – a sign that it has no image.
Context Menu: Image Frames
Here is the context menu introduced in Working With Frames,ENDNOTE obtained by right-clicking inside an image frame.
- Info will give you some information about the image – the name of the file, its resolution in pixels per inch (PPI), the actual PPI as contained in the document (not to be confused with the display PPI of Scribus), its colorspace (eg, RGB, CMYK, or other), and whether export/print is enabled.
- Undo will undo the last operation on the frame. An operation which cannot be undone is clearing its contents.
- Redo gives you an opportunity to revert an undo, in case you change your mind.
- Get Image… of course will be used to load an image file into the frame, generating a file dialog. If you use this option for a frame which already has content, that content will be replaced.Image types which can be loaded into an image frame are GIF, JPG, PNG, XPM, TIFF, PSD, EPS, and PDF.
- Image Visible – a checkbox to choose not to display the frame's image by unchecking. You might do this to speed up working with a document, by eliminating the time to refresh the screen when scrolling in the document. This will only affect the display, not whether the image is exported to PDF or printed. A frame which has an image, yet is not being shown will have a red cross from the diagonals.
- Preview Settings allow for low, normal, and high resolution displays. Lower resolutions speed up screen refreshes. This does not affect the resolution in the final PDF or a print.
- Image Effects allows for a limited scope of image alterations. See the section Image Effects.ENDNOTE
- Edit Image... will load your image file into an appropriate image editor, such as GIMP. This will be a destructive edit. If your image source cannot be edited (PDF, for example), this choice will not appear in the context menu. You can set the path your image editing program of choice in File > Preferences > External Tools.
- Update Image will refresh your image frame on the screen and makes only sense if it had been edited in an image editor while the Scribus docment is open.
- Adjust Frame to Image: If you have just loaded the image, the size is determined by the image frame. Choosing this option will enlarge the frame to the size of your image.
- Attributes. A frame may have a number of attributes which can be used for various purposes, such as generating a table of contents. This is discussed elsewhere in the manual. While it's not possible to use image frames for a table of contents, you can save other other attributes, like eg. the creator of the image.
- Is Locked will lock the frame in all respects – its contents, size, position, and other features.
- Size is Locked locks only the size of the frame.
- Send to Scrapbook will send a copy of this frame to the Scrapbook.ENDNOTE The Scrapbook is a folder where frames and other content can be saved, and reused. Sending to the Scrapbook does not delete the frame from the current document. Moreover, it will also make it available in other documents. See the section about the Scrapbook.
- Send to Layer will only be present if you have more than one layer in your document, and allows you to move the frame to a different layer – you are presented with a list of choices. See the section about layers.
- Level: Use this to move this frame toward the surface (top) of the current layer or toward its bottom.
- Convert to allows conversion to other frame types, but there are limitations, denoted by a choice being greyed out if not possible for the current frame.
- Cut, Copy, Delete are conceptually self-explanatory – the frame with its contents will be cut, copied, or deleted.
- Contents > Copy copies the image contents to a buffer.
- Contents > Paste pastes the copied image contents to a new frame, in the same relative X and Y position (relative to the frame) and same scaling as from the frame where it was copied.
- Contents > Paste Absolute pastes the image contents at the same scaling as the original, but with its original X and Y coordinates with respect to the document's coordinates. One might use this for a special effect, where one part of an image appears in one frame and some other part in a separate image frame elsewhere. You can even do this absolute pasting to a frame on another layer.
- Contents > Clear allows for deleting the content of the frame. It cannot be undone, but you will receive a dialog, asking for confirmation.
- Properties simply shows/hides the Properties Palette.
Some Notes About Image Formats
There are two basic kinds of image formats: bitmap and vector. Bitmap graphics in one way or another have assigned a point of image data as a certain color, so the image is a collection of tiny colored dots – pixels on the screen. Although printing machinery can have very high densities of these dots (DPI, or dots-per-inch), computer monitors are severely limited, and typically will show about 90 PPI (pixels per inch). In order to visually see the quality of an image on a monitor, one must use high magnification, and even then it will depend on the rendering capabilities of the software. Excessively high resolution on the screen markedly increases the rendering time whenever the screen refreshes. Some compromise is required, depending on your computer specification, however the default usually suffices.
Scribus has 3 display modes: low, normal, and high resolution, as shown in the section on the context menu > Preview Settings above. Ultimately, however, you will need to view the final PDF to check the true resolution of your document, although printing directly from Scribus can give a rough impression.
Vector graphics consist of a list of instructions for drawing the image on the screen, and adjust to the size of the display or other output. High quality fonts, ie, those which are not bitmap fonts for computer screens, are a form of vector graphic. In theory, there should be unlimited resolution of such images, but again, this is software dependent.
Let's begin by saying that TIFF (Tagged Image File Format) and PNG (Portable Network Graphics) are the recommended bitmap formats when choice is available.
- TIFF (Tagged Image File Format) is a format widely used for a variety of purposes, not only publishing, but also image transmission such as faxes. In its basic incarnation it is a one-for-one format, with each pixel represented by a data value, and thus for large images the files can be quite large. Every widely used image graphics program will be able to use TIFF. It also has an option for lossless compression (lossless meaning that no data is lost with compression or decompression). If it has a drawback it is that there are different versions of TIFF files, some of inferior quality, and one only finds this out after you use the image. In general, it is hard to go wrong with TIFF, but keep in mind that the image quality is dependent on source – we certainly don't expect much from a fax machine. TIFF supports transparency, the CMYK colorspace and ICC color space profiles.
- PNG (Portable Network Graphic) is a lossless compression format designed in part as an alternative to the patent incumbered GIF format, but also as an alternative to the complex TIFF format. One of its advantages is the ability to show transparency, but in addition, PNG does a better job than other formats where there are large areas of monochrome color and sharp transitions from one color to another. Therefore it is much preferred for things like screengrabs, images of text, and line art, where there is such a characteristic. The PNG format doesn't support the CMYK color space, but it can store ICC color space profiles.
- JPEG (Joint Photographic Experts Group) is a lossy compression format, meaning that in the process of compression some information is lost. Consequently, every time it is loaded into an image manipulation program, uncompressed, then saved (compressed) again, information is progressively lost. It is worth mentioning here that Scribus only displays and uses the file, so no further information is lost in Scribus, unless you edit the file in an external editor (context menu > Edit Image...). It cannot support transparency, but tends to do a better job than PNG where there are smooth gradients in color, thus its in common use for photography. Most cameras support JPEG, though high-end cameras allow one to choose TIFF as the format. Thus, JPEG images are ubiquitous, and there will be times when you must use them – it will do no good to convert a JPEG image to TIFF, for example, since the information is already lost. If you plan to manipulate the image, however, this may be a good idea, so that further data is not lost. If you use JPEG in Scribus, try to use a scaling of 300 DPI or greater if possible (see below) – you can easily get by with less if your output medium is on a computer screen, such as a PDF presentation or designed for the Web. The JPEG format supports the CMYK color space and ICC color space profiles.
- GIF (Graphics Interchange Format) is worth mentioning only because it is widely used on the internet. It is proprietary and uses a lossless compression. Images are only 8-bit, so you are limited to 256 colors. Most GIFs will produce unsatisfactory results in publishing, unless you have a very large image and use appropriate scaling. The GIF format neither supports the CMYK color space nor ICC color space profiles.
- XPM (X PixMap) is a simple format mainly used in computer screen icons and splashscreens. While 256 colors may be possible, in many cases there will be 128 or fewer. It is a text-based format and thus easy to edit – if you understand it. The XPM format neither supports the CMYK color space nor ICC color space profiles.
- PSD (Photoshop Document) format, as the name implies, was designed for use with Adobe Photoshop, and therefore contains the information needed by Photoshop to save image files for editing in Photoshop – transparency, clipping paths, alpha channels, spot colors, and duotone settings. Scribus has some limited, yet increasing ability to import PSD files. The PSD format supports the CMYK color space and ICC color space profiles. See Extended Image Properties for more information about special features for PSD files.
- PDF (Portable Document Format), created by Adobe Systems, is mentioned here because, when Scribus loads a PDF to an image frame, it will rasterize, or convert it to a bitmap, using Ghostscript. Thus, you have the same considerations as far as image quality. There are settings to maximize this resolution in your final product. As of this writing, Scribus can only import the first page of any PDF document, so you must use other software – both open source (free) and proprietary choices are available – to break a PDF into single page documents .
- EPS (Encapsulated Postscript), similar to PDFs, can be imported into an image frame, and like PDFs will be rasterized. One would ideally want to import an EPS directly as a vector graphic, but depending on its contents, this may not be possible.
Progressive Files: TIFF, PNG, JPEG and even TIFF files can use a technique called "Interlacing". It is a means to transfer an image gradually while using a slow network connection. Users will first see a low quality preview that slowly improves. If you want to print your images, make sure you're not working with progressive files!
Loading an Image into the Frame
When you first create an image frame, it will be blank except for a black X drawn from opposite corners, denoting the fact that there is no image.
Load an image from the context menu (right-click in frame) > Get Image (keyboard: Ctrl+D), from the menu File > Import > Get Image (or its keyboard equivalents). By default, the image will be loaded at its native size, with the upper left corner of the frame the upper left corner of the image.
It is conceivable that you may be able to simply resize the frame, but most likely you will need to adjust scaling of the image. If you know the final size you want the frame to be, follow the directions in Working With Frames then go to the Image tab of the Properties Palette.
Properties: Image Tab
If your frame is already the correct size, click “Scale to Frame Size”. Subsequent adjustments in frame size will adjust scaling to continue to fill the frame size. Clicking back to “Free Scaling” will allow you to crop edges, reposition, or change scaling.
While it might at first seem difficult to make a frame of the precisely needed size but at a certain width or height, try this sequence:
1. Make your frame of the appropriate width or height - let's say you want a width of 300 points
2. Load the image
3. Click Scale Image to Frame in Properties > Image tab
4. Adjust height so that width dimension is filled
5. Right click for context menu, select Adjust Frame to Image
Scaling and Repositioning the Image
With the mouse on the frame:
- Hold down Shift+Ctrl+Alt. Now clicking and dragging inside the frame will allow you to adjust the position of the image inside the frame (the frame stays in place). As soon as you let up on the keys, you go back to moving the Fame.
- Double Click the frame, or click on the Edit Contents of Frame icon on the toolbar (keyboard: E) – note that this will not happen if “Scale Image to Size” is selected. This works like holding down Shift+Ctrl+Alt, except that you stay in the image-moving mode until you click back to Select Item on the Toolbar, or click outside the frame.
You cannot resize the image directly with the mouse on the frame. Use the Image tab of the Properties Palette as described next.
With the Properties window:
X-Pos, Y-Pos: These refer to the offset of the image (left upper corner) inside the frame.
X-Scale, Y-Scale, Actual X-DPI, Actual Y-DPI: linked by default, click the chain to unlink. Note that changing the DPI settings doesn't change the actual resolution of an image, but just the size on a page. Do not attempt use the DPI option to achieve a higher quality output as it does not resample the source image but simply resizes it. You shouldn't be surprised that setting a lower DPI value will result in a higher percentage and thus in an enlarged image: a lower resolution without removing pixels creates a larger image in the frame.
Spreading Images over Many Pages
In Scribus you can spread an image over more than one page. For instance, if you want to use an image with a landscape as a background for two facing pages, you can create one image frame and draw it across the page boundaries. When you export your file to PDF, Scribus will automatically cut the image frame in the middle. Note that to use this feature reliably, you have set the gap between pages to zero in File > Document Setup > Display. This feature works for facing pages as well as for vertical spreads.