Transparent Images

[roban]

I've read a lot of tutorials about how to do this from a jpeg and I was wondering if anyone has a great way to do this. I have problems with the lasso tool. I guess I don't have the patience for it and the magic eraser doesn't seem to be precise enough. For instance I had to try to remove the white background between bicycle wheel spokes. A very tedious process to say the least. Saving as a png is far better that as a gif I have found. Any input about this process would be much appreciated.

[notjustgraphics]

Hey Roban

Removing backgrounds from images is always tough... especially if the image is complex or has lots of thin edges (ie. a persons hair).

Generally, i start with the 'extract' filter in Photoshop CS3 and then fine tune the output by editing the pixels.

It's also a good idea to use the 'Burn' tool to burn your edges a litle bit... this is especially effective if the object is going over a dark-ish background.

If the background you need to remove is a solid colour, you can also use the Select >> Color Range tool. This will select all pixels that match a certain range of colours, so if the subject has some color that matches the background, you may have to deselect that area after you've done the Select >> Color Range.

The Select >> Color range is best used when the edges of the subject are considerbaly different in color than the background.

As for file types... PNG is your best bet for web use. GIF's are restricted to a maximum of 256 colours (Including transparent) and use Binary Transparency which means each pixel is either 'on' or 'off'.

PNG's use alpha transparency which means each pixel can have a percentage value for opacity This makes edges a lot smoother and you dont have the 'ghost' problem you have with gifs.

Cheers.

Mike.

[turvas]

If you don't have the patience to use the lasso tool, use the pen tool instead. It has everything the lasso has, and even more. You can edit the path, add to it, remove from it, add curves and lots more.

[roban]

Thanks for the tips. There's a lot to practice with.

[VinzPhotos]

Originally Posted by notjustgraphics

Generally, i start with the 'extract' filter in Photoshop CS3 and then fine tune the output by editing the pixels.

Never liked that one. It just doesn't work properly I feel. If you want to use tool I would go for KnockOut by Corel. Principles are the same as the extract filter, but the results are so much better.

Use the polygon lasso. This gives you the most control, even on curves, just click more times. You probably will feather the edge 1 or 2 px afterwards anyway. Also, don't try to select the whole subject in one time. Do little pieces in add-mode. This way, when you screw up a click or two you can just go back a step and won't have to start all over again...

That said: extracting is never a simple process; well at least when you are not simply extracting some sort of jar. It is always a process of several steps. To me that seems good, otherwise everybody could do it. There is no one magic recipe to do it.

Sometimes I start with picking one of the channels as a base for a mask. Use a curve to increase contrast in such a way it represents the mask as best as possible. Then use Treshold to get pure B&W. Finally get your brushes out and fine-tune the mask.

Lots of times (certainly with models) I will turn to KnockOut though. Nothing beats that.

A final tip is not to "cut-out" the image, but use a layer-mask instead. This way you can always modify the masking after you have placed the image in its new surroundings.

Regards,
<<< Vinz >>>

2008 Homepage - Vincent Klijn Photography

[roban]

Thanks for the feedback Vinz it's very helpful and I will look into Corel. I have had some success with the color range selector in PS. I am only deleting a white background and although it doesn't do the whole job cleanly I find I can go back over it with the eraser tool to clean up any missed spots.

You are correct in saying it is not an easy process.

[notjustgraphics]

WoW!

I find the extract tool works very well...

One of the things you have to remember to do is control your brush size in relation to the detail of the edge, but like any tool, it's not magic.. just magical!

I've heard Knockout is good too.. but I've never used it... I've never liked any Corel software unfortunately, not for its effectiveness, but for the usability... i think there is a lot of room for personal preference in these types of editors. Comfort with a specific interface can make a lot of difference.

Cheers.

Mike.

[tamlin]

I've tried a number of 3rd-party masking tools including KnockOut, Fluid Mask and Extensis Mask Pro and, while they've all got their advantages and seem to work well, I always find myself returning to Photoshop's built-in tools if I want to do some masking/extraction/background-removal quickly and with the minimum of messing about. I guess it's like Mike says - familiarity with the tools and the interface counts for alot.