photography: gelling flash & post-processing for deep blue skies

photography: gelling flash for late afternoon sun (& deep blue skies)

The warm light from the nearly-setting sun, accentuated with gelled flash. Towards the end of the recent photography workshop, we were shooting on the rooftop – the warm tone of the sunlight contrasting beautifully with the blue sky.

To punch it even more, we added gelled flash via an off-camera speedlight in a softbox. We had to gel the speedlight of course, to make sure the blue color balance of the flash didn’t kill the natural light. We used a 1/2 CTS gel here which brought the flash’s WB down to around 3700K. (This photo of our model, Melanie, was taken by Rosario.)



gelling flash & post-processing for deep blue skies

Working in the shadow side of this structure, the only light on Anelisa is from the (gelled) off-camera flash. The blue sky was enhanced a bit in editing the RAW file.

  • camera settings: 1/250 @ f/4 @ 200 ISO


For a punchier image, I pulled the Blacks down a bit, and nudged the Contrast up.

The blue sky, which is already enhanced because of the warm color from the flash, was then made more intense with adjustments to the Blue tones in the HSL tab. I pulled up the Saturation for Blue, and then pulled the Luminance down a touch. This didn’t affect anything other than the blue sky, since nothing else in the frame had blue colors.

In the final image above, I also used the local adjustments to to selectively pull down the exposure around the edges of the frame. This created a more vignetted effect to the side of the building.

Here is the SOOC test shot as comparison:


gelling your flash


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off-camera flash gear used (and equivalents)

The soft boxes used here was the Profoto 1.3′ x 2′ softbox (vendor), which I specifically got for the workshops – gear updated: flash photography workshops. The softbox was mounded on a Profoto RFi Speedrings for dual speedlights (vendor), to enable two speed lights in a single softbox. But any of the soft boxes listed below would’ve worked just as well.


10 Comments, Add Your Own

  1. 4 says

    “The blue sky, which is already enhanced because of the warm color from the flash…”

    Hi Neil
    I wonder if you can advise how the blue sky came to be enhanced because of any colour from the flash as surely the sky is too far away to be directly affected (or otherwise) by the flash. Or am I correct in assuming the the gelling of the flash on the model simply created a greater contrast in colour between that on the model and that of the sky?
    Or have I missed something here?

  2. 5 says

    By correcting for the color cast introduced with the 1/2 CTS gel (which makes the skin tones MUCH warmer), the sky shifts more towards blue.

  3. 6 says

    Which speedlight(s) were you using? A good way to keep the sky a deep blue color is to make sure you’re shooting at a fairly fast shutter speed (letting in less ambient light yields a darker sky), but this means you have to shoot wide open (or close to it), which means the speedlight is probably in HSS mode. Shooting in HSS mode means the speedlight is putting out a lot less light; combine that with having the speedlight shrouded by a gel and hidden behind a softbox, and it’s amazing you were still able to get so much light on your subject! So I was just wondering which speedlight(s) you used here.

  4. 7EHRETic says

    Hi Neil,

    Hope your doing well since our workshop last year ! ;-)

    I’m wondering how do you gel bigger strobes + softboxes ? I’m owning now a Elinchrom Quadra Hybrid generator and I try to figure out how I can compensate the color temperature from such flashes.

    There is by Elinchrom the inner deflector that can be geled but I’m asking myself if there not something less “hand self made” for a solution… ;-)

    Keep going, your blog is amazing, I’m thankfull for all I’ve learned from you !!!

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