How to precisely extract an image ?

[thedom]

When watching shows lately, I realized that some of you are really experts with "extracting" an image.

I still have a lot of trouble to do it.

I have Photoshop CS and here are the method avalaible I know to do such a job :

- Filter > Extract

- Magic Wand Tool

But both methods take a lot of time, at least how I do the job.

And the result is not precise.

Could you please explain how you proceed, or if you know an other method or an other tool to extract an image.

Thanks to all of you for you help and suggestions.

[Severn Bore]

Hi

For precise extractions the pen tool is very helpful, although it takes a little practice to understand how it works. Some people use it in combination with quick mask for easier feathering of edges.

Severn Bore

[ContaxMan]

But both methods take a lot of time, at least how I do the job.

That's the way it is, I'm afraid.

But here are some pointers:

1. use rough selections to outline the object - any tool: magic wand, magnetic & polygonal lasso, pen tool if it's a "graphic type" shape say a car or building, colour range, etc.

2. save the rough selection then use quick mask to refine it.

3. I prefer to work on the selection itself (loaded from the channels palette) and refine it using minimise/maximise filters, gaussian blur, etc to soften it.

4. a graphic tablet, e.g. wacom, is a huge help in all of this.

So to sum up -select roughly first then refine later. Keep the selection so that you can reload and edit it if you're not happy with the first result. Get used to working with masks and/or quick mask.

[ronwil]

My grandson, David, demonstrated his method to our AV Group. He used the polygonal lasso tool to "roughly" select the image then used Quick Mask to either add or delete parts of the selection using the brush tool. However, something I would never be able to match was the speed at which he was able to work. I did use his method for the portraits in my AV Group Intro, referred to in my topic "Versions 4 and 5 - Interim Arrangements" on 21 June 2006. I found using the polygonal lasso tool needed less concentration than the magnetic one.

Ron [uK]

[Ken Cox]

Dom

some links to add to your arsenal

http://www.google.ca/search?hl=en&q=Magic+...le+Search&meta=

http://www.russellbrown.com/cool_links.html

http://www.russellbrown.com/tips_tech.html

http://www.radiantvista.com/video_tutorials/

ken

[Lin Evans]

When watching shows lately, I realized that some of you are really experts with "extracting" an image.

I still have a lot of trouble to do it.

I have Photoshop CS and here are the method avalaible I know to do such a job :

- Filter > Extract

- Magic Wand Tool

But both methods take a lot of time, at least how I do the job.

And the result is not precise.

Could you please explain how you proceed, or if you know an other method or an other tool to extract an image.

Thanks to all of you for you help and suggestions.

Hi Dom,

There are perhaps as many ways to do this as there are photographers - LOL. There are myriad masking tools - some work better than others. Years ago I went through the majority of these and finally decided that the best and most precise way for me was to simply use the eraser tool and sometimes the history brush.

It's time consuming, but do get a perfect extraction you really need to work at the single pixel level. What I do today, for example to make a PNG file containing an extracted image, is to first determine the original image dimensions in pixels (Image, Image Size) in PhotoShop, then create a new transparency of the same dimensions. Next I do a Select All, Edit, Copy on the image to be extracted. Close that image then do Edit, Paste over the open transparency which leaves a two layer file with the transparency under the original image. I use the Eraser tool at 100% opacity with a very large brush to quickly cut out the rough image I want then zoom in close and select a smaller brush to cut to the pixel level. If it's something which then needs all or some or part of the edges feathered - I just set the opacity levels on the Eraser Brush to various values and lightly brush the edges to make them slightly less than opaque so that they blend at the last couple pixels or so with the background the image will be overlaid with. Finally, I crop as closely as practical to minimize the PNG file size. Working this way I can get as perfect an extraction as I need depending on the final use of the image.

This method may not work for everyone and using various masking tools is quicker, but there is no way which is more precise.

Best regards,

Lin

[JohnFeg]

When watching shows lately, I realized that some of you are really experts with "extracting" an image.

Dominique,

I have scanned, from an excellent CS2 Treatise, an article on the use of the Extract Tool. I found this little tutorial to be very useful.

However, having scanned it at a reasonablr resolution (4 pages) and zipped it, it still comes out at 5.2 Mb.

Let me know if you want me to send it.

John

[bjc]

(IMHO) there is only one way to accurately isolate an (complex) object onto a separate layer.

1 – loosely select around the chosen object with (say) the Freehand Lasso Tool – this can be done quickly as you only need to roughly surround the object with the ‘selection’.

2 – click the right mouse button and choose Layer via Copy (this places a copy of the selected object onto a new Layer above the original)

3 – add a Layer Mask to that Layer by clicking on the Layer Mask icon ( the grey square with a white circle in the centre of it), at the bottom of the Layers Palette.

4 – switch off visibility to the Background image – or better still, introduce a new empty Layer filled with Black (or White) and place it below the new object Layer.

5 – with a suitably sized, medium soft brush, and the foreground (paint) colour set to Black, paint-out-visibility to all the pixels you DON’T want to see. (make sure that the Layer Mask is ‘active’ before applying paint to the Mask by left-clicking on the Layer Mask itself in the Layers palette – the Layer Mask is the white rectangle to the right of the Layer thumbnail) Correct for errors by painting-back-in-visibility to erroneously hidden pixels with WHITE paint.

((if you are using a Black or White underlay Layer to help you determine the accuracy of your ‘cut-out’, invert the underlay colour (press Ctrl+’i’ on your keyboard), before you finalise the process just to double-check for errors))

6 – save a copy of your image in it’s current state (as a PSD).

6 – if you wish to save the results of your efforts as a transparency GIF or PNG, first crop away any unneeded image area (crop tool), then resize the image to the physical size you want it to be, switch off visibility to all Layers apart from your object Layer, click on File > Save for Web and select your chosen file format.

The above may sound fairly complex at first – but it’s actually the quickest, most straightforward, and most precise method of making a perfect cut-out (of complex objects) of all the options available. However, for Circles, Rectangles and simple Graphics the Pen Tool and/or standard Selection Tools are by far the quickest option.

bjc

[thedom]

Thank you for your answer guys !

But unfortunately, I will not be able to practice until my pc at home is repaired...

Probably not before going back from vaccation.

It means middle of August.

Life is unfair !

[TommyBurns]

Hi

An excellent tool for producing precise cutouts is Fluid Mask a photoshop plugin look up at www.vertustech.com/ an expensive tool but it is the most advanced program of its type. Also try Katrin Eismann's book called Photoshop Masking & Compositing which shows just about every way an image can be cutout. Hope this helps.

Regards

Tommy

[alrobin]

(IMHO) there is only one way to accurately isolate an (complex) object onto a separate layer.

...... snip ......

5 – with a suitably sized, medium soft brush, and the foreground (paint) colour set to Black, paint-out-visibility to all the pixels you DON’T want to see. (make sure that the Layer Mask is ‘active’ before applying paint to the Mask by left-clicking on the Layer Mask itself in the Layers palette – the Layer Mask is the white rectangle to the right of the Layer thumbnail) Correct for errors by painting-back-in-visibility to erroneously hidden pixels with WHITE paint.

...... snip ......

The above may sound fairly complex at first – but it’s actually the quickest, most straightforward, and most precise method of making a perfect cut-out (of complex objects) of all the options available.

One nice feature of this method is that, because it uses layer masking, it is "non-destructive" and completely "un-doable", using the technique that bjc describes above in his post.

[dagrace]

Dominique,

I have scanned, from an excellent CS2 Treatise, an article on the use of the Extract Tool. I found this little tutorial to be very useful.

However, having scanned it at a reasonablr resolution (4 pages) and zipped it, it still comes out at 5.2 Mb.

Let me know if you want me to send it.

John

I would be interested if you can email me a copy, or put it somewhere where I can download it. I found a few articles about Extract Tool but they are very fundamental.

Thanks.

[JohnFeg]

I would be interested if you can email me a copy, or put it somewhere where I can download it. I found a few articles about Extract Tool but they are very fundamental.

Thanks.

No problem. Send me a personal message and I'll mail it to you.

John

[ContaxMan]

Russell Brown has recently posted two excellent movie tutorials on this very topic. Look for "Blue sky thinking" here:

Russell Browns Tips

[thedom]

Dominique,

I have scanned, from an excellent CS2 Treatise, an article on the use of the Extract Tool. I found this little tutorial to be very useful.

However, having scanned it at a reasonablr resolution (4 pages) and zipped it, it still comes out at 5.2 Mb.

Let me know if you want me to send it.

John

John,

Thank you very much for sending me this article.

It's now avalaible for everyone here on TheDom Sharing Place.