This is part 2 of my how-to series on how I did the post-processing on my Montreal images. If you haven't already read part 1 then I strongly recommend starting there first.
Camera Raw
As mentioned in part 1, the first piece of flexibility you get with this workflow is in being able to re-visit your raw developing settings after you see the effect. This first image shows what the initial effect looked like for this particular image. In this case, I was very happy with the black and white image but I wanted to adjust things after I saw the effect. In this case, I liked what I was seeing in the mix of cold and warm light from taking this shot relatively early in the morning and I wanted to emphasize that further.
Since I was working with a smart object, this is a simple matter of opening the smart object from the layers palette which puts you back into Adobe Camera Raw. The one downside I found with this workflow is that I much prefer working in Lightroom and while the adjustments in Camera Raw are the same the interface isn't so I do find I'm not as efficient working in Camera Raw. In this case though, I simply made some modifications to the saturation for the blues and the yellows.
This produced the second image shown here. Overall, I was happy with the look but I found that in some specific areas things had gotten a little too blue and I wanted to tone that down. Again, I was able to go into Camera Raw and make some adjustments, this time, I used an adjustment brush to reduce the saturation in the areas I wasn't happy with.
While not shown here, I also tried further adjustments to the saturation, vibrance and colour temperature before arriving at the settings used in this case. The point is that you still have all of your raw developing tools available to you. The one caveat is that the preview in Camera Raw will only show its effects, it won't show the effect of the filter. This means that sometimes you have to make a change and then hit okay in order to see what it will look like with the smart filter applied. Once you get more familiar with what you're trying to achieve and how the colour and black and white are interacting this will get easier.
Silver Efex Pro 2
For this second image I was happy with the colour in the image but there were some things I wanted to tweak in the black and white conversion after I saw the effect. Again, this is where working with smart filters really comes in handy as you can always get back into the settings and adjust. I find this is much easier than having to undo the filter and then re-apply it, especially if you want to work iteratively by making small changes and seeing the effect. Once you get the feel for the image and how the black and white effect is working with the image you can start targeting the shortcomings more precisely and you may not have to move back and forth as often.
In the case of this image, I was relatively happy with parts of the image but I wasn't happy with the snow in the sky looking too dark (in several spots they were dark grey blobs instead of white flakes) and I felt that the top of the skyscraper was too faded out. In this case, I used Silver Efex Pro's "U-Point" technology to add several control points to adjust this. First, I brought down the flakes in the sky so that they faded away more. After that I darkened the top of the building to make it more prominent. This also had the fortunate side effect of isolating the top of the building from the effect in the sky. After that I worked on adjusting the church to even out the exposures so that it was neither too dark nor too light. I also made some adjustments in the tree on the right side of the image as I felt it was blending in too much with the church and getting lost. Adjusting the black and white conversion helped give the separation I was looking for.
As you can see from the screenshot in Silver Efex, I made significant use of the control points to get to the final image. What's nice is that all of these can be tweaked either in groups or independently. I can also turn off any of the points at any time or delete them entirely. That's definitely one of the huge perks to working with a plug-in that gives this much versatility and control.
As I made such an extensive use of control points in this image I've decided not to include images from every step. Since this is a 3rd party plug-in I also didn't want to get too bogged down in the specifics of using this one plug-in. The point though is that you can adjust the black and white conversion to suit your purposes. In some cases you need to get past the fact that the goal is not necessarily to produce a pleasing black and white image, the goal is to produce a pleasing effect with the colour. In some cases this means making changes to the black and white that don't work for that but do work once the colour is added.
Final Notes
One final note about this if you're working with Lightroom, I highly recommend not making further adjustments in Lightroom after applying this effect. The reason for this is that if you want to go back into Photoshop to adjust your effect later then you won't be able to take these Lightroom edits with you. The reason for this is that if you chose to edit in Photoshop with the Lightroom adjustments then you'll get a brand new image created (as either a TIFF or PSD file, depending on your preferences) which will not retain the smart objects or smart filters from before. Instead, you need to use "edit original" if you want to get back to your original PSD document with these still available. This is a little counter-intuitive and not how you would normally edit images from Lightroom so I wanted to make sure to mention it here.