If you like to use your current brush and erase with it, it’s annoying to have to switch to the eraser and then pick the same brush from the brushes palette, or create duplicate of all your brushes set to erase.

Just switch your brush blending mode to “Clear” and voila, now you’r erasing with your current brush. A quick shortcut to change brush blending mode to clear is control+shift+r and then control+shift+n to go back to normal mode. You can also flip through the blending modes with control+shift and then use plus and minus keys to scroll through the modes. This works with layer blend modes to, just make sure you have to move tool selected. (v)

In the Masking and removing backgrounds in photoshop tutorial we learned how do grab a mask from the channels palette, and how to enhance it with curves, dodge and burn.

Sometimes you can get a jump start on a perfect mask, using the calculations command and masking with calculations.

We will use the same photo of the flower, just to stay in familiar territory, so if you have not download that photo, click on the image below a couple times and download the large version and load it into photoshop.

redflower channel masking photo

With the flower layer selected, go the to channels palette and from the image menu select the calculations command.

photoshop calculations command

Yeah, scary dialog time I know

All the calculations command allows you to do, is choose 2 channels and apply a blending mode, it’s realy not that scary now is it?.

What you do is select the two channels that are most different from eachother by using the source 1 and source 2 Channel dropdown lists. For this image, that would be the red channel for source 1 and the blue channel for source 2

Now we want to apply a blending mode that creates a target alpha channel (Mask) with the most contrast. This is largely a trial and error kinda deal. You know you are looking for something that makes the background black, and the object you want to mask white, or the other way around. What’s black and what’s white doesn’t matter, since you can always just hit control+i to invert the resulting mask.

To get a feel for what will happen, go through the list of blending modes in the blending modes dropdown list and watch what happens. Also, for each blending mode you select, try checking off the Invert checkboxes and see what happens. This is why I told you it’s largely a trial and error process. Nobody is going to remember what each blending mode will do with invert on/off for all the modes since the effect they will have is dependant on the colors and luminace in the image and no two will be alike.

Many times though, the blending mode that is only available here in the calculations command.. Add is going to work, and that’s the one we will use for this tutorial.

Select the red channel for source 1 and the blue channel for source 2. Set the blending mode to Add, opacity to 100 (Opacity is rarely changed ffrom 100%), Offset to -200 and leave the Scale set at 1. Lastly, put a checkmark in invert for the Blue channel.

Hey, would you look at that, that looks like the start of a super mask.

Make sure the Result dropdown listbox is set to New Channel which is the default unless you changed it, and hit OK.

calculations channelmask 1

Now’s the time for some curves to bump up the white and blacks, so hit control+m.

Set the black input levels to 120 and the white input levels to 225, that’s what I found the best compromise. Feel free to play around and see if you can make it better and then hit OK.

photoshop calculations curves

Now we burn the grey areas like we already learned, and dodge the white areas to further enchance the white and black areas. The process is the same, but notice this time you don’t have the problems with the ratty edges, and the grey background and white flower responds much better to the dodge and burn tools, making the whole process a lot faster.

I’m going to stop with the images showing progressions of the mask, you should be flying through the mask by now anyway

Take care of the rest of the background by painting it over with black and paint the inside of the flower white.

Invert the mask to check if you got everything. Nope, still some stuff there. A quick dodge and burn and that goes away with no effort.

Invert the mask back again, control click on it to load it as a selection and go back to the layers palette. Doubleclick the background layer to turn it into a normal layer, and with the selection still active click on add layer mask.

Add a black background behind the masked out flower and notice that this time we have no background bleed either. Using calculations for masking made our masking job much faster and painless.

Now you are ready to read: Masking in the LAB Color space (Advanced)

Make sure nothing in the scene with your subject moves, this goes for changing lights, moving flags or gobos etc.., the scene must be static. Shoot on a stand and use a remote to trigger the camera so you don’t get any movements at all.

This technique works best of you are already shooting on white seamless backgrounds.

Now take the photo of your subject. Carefully remove the subject from the scene and take another photo.

Import the 2 photos into Photoshop and put them on different layers, order doesn’t matter.

Now for the magic. Select whatever layer is the top layer and change the blending mode to Difference and voila, whatever was changed will become black and the rest of the scene will be white or at least very bright. Hit control+shift+alt+e to create a copy on a new layer on top of all the others and hit control+u and pull the saturation down to make the mask black and white. Go to your channels palette and grab the blue channel and make a copy of it. Now hit control+m to bring up curves and drag the white/black input sliders to wards the middle to make the mask all black and white and clean up any gray areas. Control+click the channel to load it as a selection and go the the layers palette and select your original image, click add layer mask and there’s your masked out image.

Here’s my take on how to create fake bloom in photoshop.

First duplicate your original layer.

Now go to filters/blur/lens blur. Set the radius high, around 80 or so and adjust the specular highlight brightness so the brightest areas of the photo blows out. Play around with curvature and rotation if you like. Be aware that the lens blur filter is dog ass sloooow so expect to wait a while on large images. Ok the changes.

The reason we use lens blur and not gausian blur like so many other tutorials is that we want to emulate as closely as possible the effect of bloom in camera and gausian blur will just not be realistic.

Now turn of all but this new layer, we are going to use it to create what is called a “found mask”, a mask that is derived from the image with no brushwork. Go the the channels palette and select the blue layer and drag a copy of it to the new channel icon below the channels palette. Name your new layer “bloom mask” and then hit control+m to open up the curves dialog box.

In the curves dialog box grab the black input triangle below the grid and drag it a bit towards the middle, you want to make the black areas of the bloom mask channel black, don’t go to far as that will create harsh transitions. Grab the white input slider and drag that a bit towards the middle also, not to much, just enough that you see some of the brightest areas go all white. Ok out of the curves dialog box.

Go back to your layers palette and delete the blurred layer, we are done with that. Select the original layer and hit control+j to jump a new copy of it. With the new copy selected, go back to the channels palette and control+click on the bloom mask channel to create a selection from it.

Go back to the layers palette and now click on the add layer mask icon below the layers palette and you have created your “found mask” layer.

Set the layers blending mode to screen and watch the bloom come alive. If the bloome areas are to sharp, select the layer mask and hit it with some gausian blur to smooth it out. You can also try selecting the layer and add a hue/saturation adjustment layer and adjust the colors to be a bit more yellow to simulate sunlight bloom better.

If you realy want to hit this effect over the head, select the channel mask on the layer and drag it to the trashcan icon, when asked, select “apply mask” before deleting. Now select the bloom layer and add some motion blur, adjust the angle of the motion blur so it follows the direction of the light, this creates cool “god rays” and can look amazing on sunshine landscape photos, if the rays become to streaky, hit the layer with some gausion blur after you apply the motion blur.

You may also want to try some other blending modes than screen to see if you get effects that you like, the possibilities are endless.

The way I do it I simply hit control+j to jump a new copy of the original layer, draw a selection around the speculars that offends on this new layer, bring up the gausian blur and adjust the radius to wipe out the specular. Sometimes before I do this I feather the selection a bit.

This works great for very smooth surfaces like glass and metal. But what if you’r product has a pronounced texture that the blur will also smooth out and make it obvious what’s been done?

Model retouching uses a great technique to smooth out skin, you simply blur the skin, then add back the amount of texture on top needed to make the skin believeable again, and it’s very simple.

First blur the specular like described above. Make sure you save the selection you draw around the specular. Now select the original layer that’s not been blurred, bring back your selection and hit control+j to jump a copy. Drag the copy so it’s above the blurred version. Put this copy into soft light blending mode. From the filters menu select other/highpass.

The soft light blending mode uses neutral gray to denote transparent, so everything that’s grey will simply not be visible. The highpass filter makes everything but sharp contrasting edges grey, the higher the amount, the more of the image will show through, so you want to adjust the filter so the amount of texture you want “escapes” and shows through. You can think of this technique as a sieve for the texture, the larger the highpass radius, the larger pieces of the texture can fall through the sieve.

Sometimes soft light is not hard enough so if your texture is not showing properly try the hard light, vivid light or liniar light blending modes instead.

Expose so the highlights are good and the shadows will blow, expose so the shadows are good and the highlights will blow, the solution is to take 2 exposures, 1 for the highlights and 1 for the shadows and drop them on top of eachother, the problem here is that no matter how good your tripod is and how high the shutter speed is, there will ALLWAYS be a slight difference, enough to slightly blur the image.

The solution is then to put the two images in top of eachother on different layers and put the topmost layer into difference or exclusion mode, in exclusion mode, when the two images gets closer and closer to being 100% aligned the image will turn more and more black, if they are 100% aligned the canvas will turn black and you know you have a 100% alignment, at which point you can put the blending mode back to normal and continue doing masking work to blend the 2 exposures.

Difference and exclusion blending modes are also usefull when you are not sure if a conversion is being destructive or not. For example switching color modes between LAB and RGB. Keep a copy of the original switch modes and then put the two versions on top of eachother, switch top layer to exclusion mode and if the pixels does not turn black you know that you just did a desctructive mode switch.

Dodging and burning is a technique from the wet darkroom where the photograper would let the emulsion darken or lighten areas to control the exposure and for artistic effects.

In photoshop we can dodge and burn to artistically enhance our photos, now photoshop has brush tools specifically for this purpose, the problem with them is that to use them you are doing desctructive edits, NO GOOD.

Color dodge and color burn blending modes to the resque. Create 2 blank layers above the background layer, name one dodging and the other burning. Set the Burning layer to, yes you guessed it, Color Burn blending mode and fill it with white, and the Dodging layer to Color Dodge blending mode and fill it with black.

Now go select your paintbrush tool, set the opacity real low, like 20%. To dodge areas paint on the dodging mode with white, and to burn paint on the burn layer with white. This technique is also commonly called “painting with light” and is a skill you need to develop by practicing a lot, it’s useually most effective with photos with lots of detail, like a photo of a forest or other dramatic landscape, look at the photo and see where the light and shadows fall and try to enhance them by dodging and burning, the nice thing is that you can reverse the effect and paint it away by using the inverse color so it’s very flexible and you can go back and forth endlessly without harming the original pixels of the image.