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Halation


arthur_gottschalk

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<p>If you are asking about digital post processing of an image to simulate this effect, it's easy to come reasonably close if you have a photo editing program with layers: Duplicate the image, and apply a blur to the new layer. Then, drop the opacity so that the blur doesn't overwhelm the original image. If you want only the effect of spreading of the highlights, set the blending mode to "lighten" or "screen" and re-tweak the opacity. If you want both the highlights and shadow areas to spread, set the blend mode to "normal" or "overlay" (and re-tweak the opacity to taste).</p>

<p>This is a common look, and so there are a huge number of variants of this general procedure, but most more or less generally follow the above description. If you don't like a DIY approach, there are even plugins that can be adjusted to produce halation-like halos, e.g., http://www.richardrosenman.com/project/?cid=204.</p>

<p>One can kinda-sorta simulate this effect using an optical filter, but you'll have to ask someone else which diffusing filter comes the closest. Because of the additional control offered by digital PP, I only use optical filters any more for very specific effects (eg, polarizing) that can't be done in post processing.</p>

<p>HTH,</p>

<p>Tom M</p>

<p>HTH,</p>

<p>Tom M</p>

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<p>True halation is caused by having a bright light source in the image, which spreads due to scattering in the film emulsion. It's a function of the film used rather than a filter effect. However, I suspect that the effect illustrated in the fashion spread was simply highlight diffusion.</p>

<p>Highlight spreading or diffusion can be generated in a number of ways:<br>

1) By the lens used, for example the Imagon "soft focus" lens discussed in an adjacent thread, or by a lens that shows severe spherical aberration. A lens with a damaged front element will often show the effect too!<br>

2) By using a filter over the lens. A piece of translucent material such as part of a pair of ladies' tights or stockings; a UV filter lightly smeared with vaseline or heavily fingerprinted; a dedicated soft focus filter or a lightly ground piece of glass.<br>

3) As stated above, by using an image editor to apply gaussian blur to a highlight layer and then recombining with the original image.</p>

 

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<p>Just a minor clarification to Rodeo's reply: In my post, I intentionally avoided specifying the type of blur as "Gaussian". The most realistic simulations of halation (eg, the plugin that I cited) do not use a simple Gaussian blur. They go to great lengths to generate other point spread functions that more closely mimic the various types of light diffusion (eg, filter, lens, film).</p>

<p>Tom M</p>

<p> </p>

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<p>I agree there Tom. Gaussian blur doesn't give the most accurate simulation, but it's readily available in PS and doesn't require any additional plugins.</p>

<p>Here's a quick demo of the technique I described above, of creating a duplicate layer, applying G-blur, turning it into a monochrome highlight mask, then blending using lighten mode and adjusting the blend opacity by eye. This was all done using GIMP, which doesn't have any fancy blur modes.</p>

<p>The original photo was a quick candid taken in a cafe. The horrible mixed fluorescent and tungsten lighting has given it a "cross-processed" look, finished off with a bit of colour tweaking and then the blur layer added.</p><div>00ZUf7-408133584.JPG.742a9ac5f811c14cc7f9321e5a1626fe.JPG</div>

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<p>Rodeo - nice job. You got a wonderful, almost Japanese / porcelain makeup look to her skin, but I would agree with Arthur, that not what I think of when I think of halation.</p>

<p>Arthur, it sounds like you probably can't provide a link to the specific image that you had in mind. However, can you find some similar images, say, using Google Image search, and provide links to those, or at least an image of your own to which you want to add a halation effect?</p>

<p>Tom M</p>

 

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<p>If you're going the analog route,<br>

Hasselblad had "Softar" filters in varying degrees of halation. I have one but haven't used it in ages. They were(?) made by Zeiss and have a dimpled surface.<br>

Hoya made the "Duto" filter. It was similar to the Softar but with concentric rings on it's surface. I used it with my 35mm gear.<br>

Have a look on that search engine. They're both there.</p>

<p>http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/filter/filter-diffusion.html</p>

 

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<blockquote>

<p>....I realize that most 19th C. pictures do not exhibit halation.</p>

</blockquote>

<p>They ought to really, since anti-halation backing wasn't used until commercial dry plates were in common use at the end of the C19th. However, true halation is more noticeable with smaller format sizes, which again didn't become popular before the introduction of commercial plates and rollfilm. Arthur, could you find a link to a suitable illustration for us?</p>

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<p>PS - I forgot to comment that the diffusion of light in the 1st three of the webpages that I cited above probably extends over longer distances in the image than you probably are thinking of. That is why I included the last one, the screen shot. In it, most of the light diffusion is very near the source, although because of the black background, even small amounts of diffused light can be seen further from the source.</p>
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<p>Any chance it could have been an IR film image? A good part of their characteristic look comes from the fact that IR films don't have an anti-halation coating.</p>

<p>E.g.:<br>

http://www.markcassino.com/b2evolution/index.php/kodak_high_speed_infrared_film or<br>

http://static.photo.net/attachments/bboard/00L/00Lvei-37540884.jpg</p>

<p>Tom M</p>

 

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