Thursday, February 14, 2008

Taking photos around town

When taking pictures outdoors, you should be conscious of the lighting sources (both direct and reflected) as well as the temperature of the light. When processing outdoor shots, don't assume that the images are colour/white balanced.

Today's shot comes from Nottingham Daily Photo, a nice little blog about life in Nottingham's city centre. This is one of my favourite photography blogs as it's shot from the hip and straight from the heart. You really get a sense of the Photographer's love for his subject matter, in this case the heart of Nottingham.

I love the effect of the shadow from the big wheel on the buildings. To further emphasize this effect, I've restored the focus to the image and made a subtle change to the white/black points using a curves adjustment layer. There are a ton of edges to work with, so I used EasySharp to handle edge sharpening. Noise wasn't an issue here; there was just a touch of noise in the sky which I removed with Noise Ninja. In less than 30 seconds, I managed to kick this image up a notch.

After the Forensic Photoshop treatment

Image analysts and retouchers have the easiest part of the process. With a shot like this, timing is everything. The hard part, the photographer's part, is lugging around the camera in hope that a shot like this will come along. Thankfully for us, he was well prepared.

Check out more daily photo sites by clicking here.



Kit Grose said...

Hi Jim,
I love the work you do, but I have one question that affects this photo and a few other ones you've shown in the past:

To my eyes, the modified image looks like it has a strong green cast over the bricks on the buildings, that is seemingly affecting the sky (turning it purple) pretty badly. While of course I wasn't there, the original looks much more natural to me.

With that in mind, is there some mathematical/levels-based heuristic you're using to figure out which way to fiddle with the curves that implies it's doing a better job of bringing the natural colour out, or are you simply manipulating the curves manually to bring out the shadow as best you can?

As a designer with around seven years worth of Photoshop experience and the son to a forensic services officer with the NSW Police in Australia, I find your blog very informative, but am simply having a hard time figuring out how you choose when to stop manipulating an image (is it by a heuristic, or simply by eye?)

I do find the sharpening and noise-reduction techniques you teach to be very compelling, but can't really wrap my head around the colour decisions.

Jim Hoerricks said...

Thanks for the comment.

Use a Threshold adjustment layer.

Bring the image all the way to white or black by sliding the slider to the left or the right.

Leave a marker in the image to identify a white and a black point by shift+clicking in the image at an appropriate point.

Cancel the Threshold adjustment.

Open the Info Palette.

Notice your two points. Their RGB values should be about equal. If you are seeing too much green vs. the others - there's your colour cast.

Adjust the image with a Curves adjustment layer until the values are equal for these two points. I try to aim for Black = 10 and White = 245. This gives some head/foot room for detail in the shadow and highlight areas.

This method takes your eye out of the equation and bases the decisions on the colour values. Use your Info palette religiously.

There are times, however, where you will want to target specific areas of an image. In these cases, I use local colour/light adjustments like masked blending modes or dodge/burn.

One thing ... remember to calibrate your monitor on a regular basis. If you have windows, light values can change by season. No windows, maintenance can change bulb vendors, thus effecting the temperature of the light that you are seeing in your work space. I try to calibrate once a month.

This biggest problem I've had with this blog is that it only allows jpeg images and it re-saves the images on upload. Sometimes, the values get tweaked a bit.

Thanks again for the comment.

Jim Hoerricks said...

I've just posted the explanation of how I perform my adjustments at the above referenced link.

Thanks again for the kind words and the comment.

My family is having a big reunion in Australia in November, centered around the Highland Games outside of Sydney. I have a friend in the SA Police and was thinking of adding a week on to the trip to offer up some local training. If you agency would like some local help, and I'm in town, just let me know ...


Jim Hoerricks

Jim Hoerricks said...

Sorry, computer glitch ... the comment should have read "your son's agency."

Kit Grose said...

Hi Jim,

Thanks for the great response (and follow-up post); my worries have been sated.

Just as an aside, my mum is the cop (and I'm a guy); I'm a graphic design graduate working in the industry. She's a forensic services officer soon to be taught the Photoshop bare essentials to allow her to process and analyse the photos she takes on site.

As a brief follow-up; does the fact that the scientific white point/black point leads to an image that looks (to me) hue-shifted mean that the eye presents a colour cast of its own? Or could it be the CCD in the camera not capturing an even spectrum/needing a filter?

Thanks again for the help!

- Kit

Jim Hoerricks said...

"an image that looks (to me) hue-shifted"

Examine the environment in which you view the image. Does it look the same on other monitors? Other platforms?

Is your workspace colour managed? If so, how often do you calibrate? A change in light bulb vendors can change the colour temperature in your room. You should consider calibrating after changing the light bulbs. Also, if you room is lit with sun light, changes in the season can effect the colour temperature in the room. Thus, consider calibrating on a schedule that includes maintenance and seasonal issues.

You do bring up a great point though, what are your eyes doing? We calibrate our workflow. How often to we check our eyes? A trip to an eye doctor each year can help. Be sure to let them know what you do for a living and what issues you may be concerned with. If you need glasses, avoid tints on the glasses that you'll wear whilst correcting images. Again, check with your optitian and be sure to completely illustrate the issues that you're concerned with.

Great questions. I'm looking forward to heading down under this November.