Positive Image

Frank Charlton

After a year's worth of hype and publicity, it finally arrives. Frank Charlton investigates Positive Image...

 While this fidelity to the colour depth of an image is admirable, there are some restrictions. Although PI runs in mono modes, tweaking complex 24-bit images on a dithered mono display isn't particularly easy to do, unless you can actually visualise what's happening. 

As you can see, PI runs happily on a mono monitor, even editing 24-bit TrueColor images 

Still, the fact that PI isn't restricted to high-colour resolutions is an admirable aim. 
PI is fully GEM-compliant, and opens any images in a standard window. It seems cleanly written too, since it runs well under multitasking systems like Geneva, MagiC and MultiTOS. It also performs admirably under 'emulators' like Gemulator and MagiCMac. The interface is sensibly designed, with tools and functions accessed through icon toolboxes as well as the menu bar. The toolboxes are excellent, with clear icons. 
It's apparent a fair amount of thought has gone into creating a clean and uncluttered interface which still lets you get at the power tucked away inside PI. 

Even under mono resolutions, TrueColor images can be saved as JPEGs 

Once working with an image, PI has a lot in common with other high-end image processors. For global work on entire images or selected blocks there's a comprehensive range of filters, covering everything from the standard Sharpen and Smooth through to more esoteric types like high-pass filters. Some filters are purely for special effects, such as one which makes images appear to be vibrating rapidly. On a Falcon, some of the filters are accelerated via the DSP, which produces noticeably faster results. Like any good image processor you can construct your own filters - or modify existing ones and save them to disk for future use. If you've used other top-end image processing packages you should be knocking up your own filters in no time. 
PI also offers tools to distort and warp your images. As well as standard rotate and resize tools, you can twist an image or block using the object and control point warp tools. While they're nowhere near as sophisticated as their counterparts in APEX Media, striking results are possible. 
A first for PI is the ability to create those pseudo-3D stereograms which caught everyone's imagination a while back. PI can create random-dot stereograms for you, although you need to prepare an image specifically for the job. The 3D depth information is built up according to the colour of each pixel in your image - colour 0 in the palette is deemed to be furthest away from the eye, with each subsequent shade rendered closer in 3D space. With a bit of practice you can create stereograms which possess a startling amount of depth. 

Warping images of friends can be fun, but don't expect anything too artistic as a result 

Block handling is extremely powerful indeed. As well as being able to select the standard square and elliptical blocks, PI offers two advanced modes for selection - autotracing and Bezier curves. Autotracing - often called a 'magic wand' will select any solid areas of colour you click on. Setting a tolerance factor allows a 'looser' selection - selecting a white pixel in a background also selects any neighbouring shades of cream or grey, while leaving darker shades unselected. 
When it comes to selecting complex objects - for a job such as lifting a person from some complex background scenery a much more powerful tool is required. PI lets you outline a complex object by drawing a series of intricate curves around the edges, which is converted to a selected block. Initially, you can draw the curves fairly loosely and drag the 'control points' later to smooth and fine-tune the outline. 
It does takes practice to use Beziers effectively, but once you crack the technique, it's a doddle to do. 

Using Bezier curves, it's possible to chop difficult objects out completely from the background 

PI uses the GEM clipboard intelligently. Every block you cut is saved to the clipboard, and can be recalled and pasted at any time - even weeks or months later, as long as the clipboard files are left intact. This is superb, and makes for trouble-free cutting and pasting, even if you suddenly need to switch off or nip into another application. 
With a package as powerful and complex as this you'd expect a steep learning curve, right? 
Not so. The 130 page A5 manual is very well written, and explains topics logically and clearly. In some aspects, it's almost a tutorial work on image processing, and the extensive glossary of graphical terms will help novice digital artists get to grips with the program. As with most image processing software experimentation is the key to learning. Thanks to the helpful manual, you fiddle with images and pick up new techniques as you go. 
Image file format support is exhaustive. 
The standard Atari formats of old like Degas and NeoChrome are supported, as are the more generic multi-platform formats like TIFF and JPEG. One glaring omission is the lack of support for CompuServe's GIF format - an image type used every day by web designers. The reason is simple - some time ago, UniSys proved they owned the LZW compression system around which GIF images are based. Basically, every program which uses the GIF format is now required to pay a license fee to UniSys for the privilege. Floppyshop decided they weren't happy about this, and so GIF support was axed. From the users point of view this means you'll need external conversion utilities to work with GIF pics. However, there is hope because PI uses external load and save modules, so the GIF module could easily be re-introduced later if Floppyshop wise up. 
Once you're happy with an image, you'll often want a printout. PI's printer support is both comprehensive and high quality. As well as a range of custom drivers for mono and colour printers like HP's DeskJet series, printing via GDOS is also supported. Any printer driver can also be redirected to a disk file for later printing. The jewel in the crown here is the inclusion of a PostScript driver - while you probably don't own a professional PostScript printer, the ability to dump the file to disk at maximum quality for output via a Bureau is useful. 

Positive Image is powerful, well-written, and damn good at the job. It's not without faults, though - as well as the lack of GIF support, there are other niggles. JPEG images can only be compressed with two default settings, 50% and 75% - which is less than flexible. PI can be awfully lethargic at some tasks, too. Some filters take forever on large images, even using the Falcon's DSP, and screen redraws can crawl along in TrueColor mode. MagiC 5 users will also be annoyed to discover PI quibbles files which use lower case letters for file extensions, for example, img instead of IMG, by saying it doesn't support that file type. Hopefully this will be corrected in the next update. 

With a little practice unusual collage images are easy to do 

So does PI compare favourably to the big boys on the Mac and PC? 
It does, yes. It provides a vast amount of image processing power at a fraction of the price users on other platforms have to cough up, and it's well behaved and stable. The modular system means new file formats can be added later without fuss. PI is still actively developed - indeed, a specific 68040 version is now available from Floppyshop for users of Falcon expansions like the AfterBurner040. At this price point, PI is an excellent program - if you're serious about processing scanned or digitised images, it's a boon. 

2nd opinion 

Let's see what Chris Good has to say about Positive image...

Scaling, pasting and blocks

A nifty Trace tool can automatically select similarly coloured areas within images which makes it easy to select to 'lift' foreground areas from distracting backgrounds. 
There are 11 different ways to 'Overlay' a block onto an image - you can even choose how each colour channel (RGB) and mask affects the block. Everything is controlled from a dialog box which appears after the block has been dragged into position within an image. 
 
Blocks cut or copied from images are saved to the Clipboard to a numbered list. 
Each block is saved with the name of the image you've cut it from. 
For example, 1 CAT.JPG, 2 CAT.JPG, 3 DOG.JPG, 4 CAT.JPG and so on. 
It's difficult to remember what each block contains without making notes - which is bad enough, but if you delete a block then save another one it is inserted in the first available slot in the list which is most confusing. 

Masks

Filters

Filters are applied to images using the Toolbar. There's a selection of standard filters including smooth, sharpen and blur along with options to load and save filters. There's even a filter editor but this is definitely one for experienced pixel pushers! 
Filters can be applied to the entire image or a marked block. The Falcon's DSP chip is used but filtering is processor intensive so expect lengthy delays. 

Warping

Retouching

• blur
• sharpen, 
• dodge
• burn, 
• rubber stamp, 
• area fill, 
• pencil, 
• paintbrush, 
• line, 
• erase and 
• spraycan.

Text handling

Overall, compared to the competition, and with continued development I'd say Positive Image is a real bargain. 

• Product name: Positive Image 1.1 
• Publisher: Floppyshop 
• Contact: 01224 586208 
• RRP: £79, launch price: £65 + P&P 
• Requires: 
• Any Atari with 1MB, 
• more memory and hard drive recommended. 
• Pros: 
• Very powerful, 
• works in all resolutions, 
• excellent manual 
• Cons: 
• No GIF support, 
• can be slow 
• Rating: 
• Frank 84% 
• Chris 85%