Whats is the best background colour/value to shoot for post processing substitution.

<p>I am shooting some flowers. I'd like to try out a variety of coloured backgrounds in Photoshop (PS). At the mo though I'd like to know what colour background is best for later removal in PS. Some of the edges of petals are semi transparent so pick up the background colour within themselves. I don't know an awful lot about PS and how a colour can be manipulated.</p>

<p>The only things I'm coming up with is to use a colour not in the subject, so I can later select that colour an know it wont overlap onto the subject itself. It sounds crude and will come unstuck when there are lots of colours in the subjects. I think there is likely a better way...but how? Would it be good if I could just use black and then somehow remove the black from the edges of the subject (I was just thinking black can be sampled in a few PS menus eg dodge / burn shadows etc and is not a common value).</p>

<p> </p>

<blockquote>

<p>"Some of the edges of petals are semi transparent so pick up the background colour within themselves."</p>

</blockquote>

<p>In that case you will most likely run into problems due to edge spill with any other colours than the neutrals, black, grey and white.</p>

<p>Your best bet might be to make sure the main subject is rendered sharp against a distant and evenly-lit, neutral background. That way you should be able to create a mask in Photoshop without too much work.</p>

<p>If on the contrary you were using a colour not in the subject, it would alter those semi-transparent areas' colours in ways very difficult to correct.</p>

<p>Assuming you have full Photoshop, the original background, modified, may be the best.</p>

<p>Duplicate your layer. On the top layer select your subject and add a layer mask - this will mask out the background and keep only your subject.</p>

<p>On the bottom layer, apply a very strong blur to the entire layer and perhaps darken it a bit. The colors through the transparent petals will blend nicely, yet your flower will stand out.</p>

<p>For the reasons mentioned above, with any background color except white, gray and black one risks color contamination. I don't like white and black because they can have too much contrast with the edges of the subject and one risks the tonal version of color contamination around finely textured edges, especially if they are even slightly OOF. So, one is left with essentially only one choice, a nice, neutral, textureless, mid-toned gray. I find this gives the least problems in post processing, assuming that one has a way to accurately select on the exact tone, saturation and hue of the specific background and lights you employ. </p>

<p>The best solution I've *ever* found for this function a plugin called Asiva Selection. Unfortunately, it is relatively old, and the company's website looks moribund. Fortunately, this plugin still works flawlessly with CS5 in 16 bit mode. It is similar to "Color Range" tool in PS, but vastly more capable. Drawing the curves (2nd citation, below) for any particular task usually takes only seconds.</p>

<p>Ctien's nice review of this software is reproduced by Asiva here:<br>

http://www.asiva.com/news/PHOTO_Techniques_Review.pdf</p>

<p>A screen shot of the user interface is here:<br>

http://www.asiva.com/products/plugins/SelectionQuickStartPC.pdf</p>

<p>Unfortunately, I couldn't immediately lay my hands on an example using the mid-toned, neutral gray background that I recommended above. However, I show an example (...no high art here ;-) ) where I used this program to quickly replace a featureless blown out sky with a blue gradient. If you have ever tried this, you know that the fine detail of the leaves and small branches on trees present a particularly difficult challenge to these sorts of cut-out / extraction tasks. As you can see from the attached images, Asiva did a very nice job, and did so with minimal work.</p>

<p>Of course, there are specialized programs to do cut-outs. I own a copy of onOne Software's Mask Pro, but I only use it instead of the vastly simpler (and less costly) Asiva Select if the background is not uniform (ie, has considerable brightness or color variation). Vertus' "Fluid Mask" is another fairly high priced option. I demo'ed it a couple of years ago, but could never get it to work as well as "Mask Pro". One final option is the new edge detection capabilities in the "Refine Edge" dialog box PS CS5. To be honest, I haven't yet had an occasion to play with this feature of cs5.</p>

<p>HTH,</p>

<p>Tom M.</p>

<p> </p><div></div>

<p>Here's the same shot after I used Asiva Select (as discussed in the previous post) to drop in a simple blue gradient in place of the blown out sky. Notice the fine detail around the leaves silhouetted against the sky. </p>

<p>Tom M.</p><div></div>

<p>Thanks Martin, Brooks and Tom.</p>

<p>For the record its CS4 that I have but only do limited things with it, so my question was really all about preperation and foresight (LOL That I don't have) so thanks for the information. Now I have a technique I can try straight off and also I know one of the terms implicated in this - 'edge spill'.</p>

<p>So I'll be trying to get a neutral grey background from now on. Thanks for your help because I'd have never figured that out at this stage myself.</p>

<p>And thanks again to Tom for going the extra mile..cheers buddy.</p>

<p>You're quite welcome, Brian. </p>

<p>After having to admit publicly that I hadn't yet tried the new "Refine Edge" capabilities in CS5, I figured out how to use it and then put it to work on the same photo that I used as an example in this thread. It worked really well and was reasonably fast. </p>

<p>The way I see it, for a photo with a relatively featureless background and miles of edge boundaries (eg, the sky peeking through the leaves on multiple trees), Asiva Select is almost certainly the quicker of the two methods. This is because one doesn't have to fiddle around painting the edges with the new brush in the "refine edge" dialog box. However, for an image with a noisy / busy / textured background, but a relatively simple boundary between the areas (eg, a horizon, around the edges of a few leaves, etc.), CS5's new technique would almost certainly win out. Also, it has a "decontaminate color" option which will hopefully remove some of the problems caused by colored backgrounds.</p>

<p>HTH.</p>

<p>Cheers,</p>

<p>Tom M.</p>

<p>Hi Tom</p>

<p>I've found the refine edge in CS4 and dabbled with a picture I did a few weeks ago. I'm hoping this post will show an actual size selection...!</p>

<p><a href="http://www.imagebam.com/image/9b579d88467047" target="_blank"><img src="http://thumbnails25.imagebam.com/8847/9b579d88467047.jpg" alt="imagebam.com" /></a><br>

Ah well no...but there is a thumbnail that I hope works. Would Asiva manage to select this subject in a fitting manner to replace the background later in CS4? There are focused hairs and unfocused hairs that are so slim when unfocused they are half hair and half background. I tried the refine edges in CS4 but my original selection (Select>Select Colour Range> Selected Colours> I selected the black background and used fuzziness to dial in) was as good as it got but was a mess trying to isolate the subject from the background (done before advised neutral mid grey was best).</p>

<p>Hi Brian -</p>

<p>I jumped from CS3 to CS5, so I don't have any personal experience with CS4. However, my understanding is that Adobe made a major improvement to the "Refine Edges" tool between CS4 and CS5. Because of this, I don't think the "Color Range" tool in CS4 is going to do an acceptable job for you. They definitely are not the same.</p>

<p>There are some very good on-line tutorials about this new tool in CS5. You might want to check them out. The first one that showed up when I searched for {photoshop cs5 "refine edge" tutorial} was this one:<br>

http://www.graphictutorials.net/video/refine-edge-in-photoshop-cs5/</p>

<p>It looks good -- short, sweet and to the point.</p>

<p>WRT your question about Asiva, after have familiarized myself with the new Adobe tool, IMHO, a decision about whether to use Asiva or the PS tool should be made on the basis of simplicity of the background. As I said in my last post, if the background is essentially featureless (ie, a gray or green screen), I would go with Asiva. OTOH, if the background has considerable texture, I would use the new PS tool.</p>

<p>HTH,</p>

<p>Tom M</p>

<p>PS - Sorry, but I can't tell much from the image you posted, even after clicking on it.</p>

<p>HTH,</p>

<p>Tom</p>

<p>Hi Tom,</p>

<p>Gone but not forgotten! I've had time to pop on and off but if someone is trying to help me then I always try and do the decent thing and give my time to them by only coming on when I can give time to their post.</p>

<p>Impresive looking video. This promps me to look into getting CS5 and system requirements. Ah my laptop looks like it is in with a shout. May well upgrade when I become <em>au fait</em> with CS4 and see what it can and can't do.</p>

<p>Thanks Tom.</p>

<p>Hi Brian - Good to hear from you and thank you!</p>

<p>Cheers,</p>

<p>Tom M</p>