This brush can be used to pack on shadows similar to the 239 brush but I personally don't use it as much for that purpose. Similar to the 239, the brush is made of white goat hair so be sure to deep clean your brushes often to maintain the color. When I got this brush 3 years ago, I forgot to paint clear polish over the MAC and number so again it got scratched off.
The 217 is really my go-to brush for 3 different applications (highlight, pigments, and paint pots).
Highlight - since the brush head is much larger than the 239, I find this much easier to use to apply highlight eyeshadow on the brow bone and blend out harsh lines from the crease. One swipe from the arch of the brow bone towards the inner and outer corner usually does the job. It is a great brush to lightly blend the highlight together with the colors at the top of the crease to help the colors blend together flawlessly.
Pigments - This is one the best brushes to apply pigments because of the large oval shape size of the brush head, making it easy to pack on the pigments without too much fall out. You can also use the 239 but I feel this is more dense and does a better job. Here I have Coppering Pigment, Fix+ and the 217 brush. I will show you the difference in pigment application with/without a mixing medium.
Similar to eyeshadow application, you want to pat on the pigments and not sweep to avoid fallout. Below I dipped the brush onto the pigment lid which has just enough product. Another method is to tap the pigment onto the cap and dip the brush into it. You can choose whichever way is more convenient for you. I generally do not dip the brush into the pigment jar itself due to sanitary reasons and generally it causes the brush to pick up too much product.
After picking up the pigment, lightly tap it onto the lids moving from either middle to either sides or from the outer corner inwards. You can go back and reapply to build up intensity. Here I applied the pigments onto the lid without a base. Notice how little fallout occurs below the eye because I used a light tapping motion as I move across the lid.
Now Coppering is a really intense khaki color with gold shimmer. Without a base, you can see the color doesn't show up very well. This is usually the case with all pigments so Fix+ is a very handy product in pigment application. You can either use a mixing medium that MAC carries or you can use Fix+ to help intensify the colors. Take the 217 brush, spray the brush with a light mist of Fix+ from a distance so it's lightly damp. You don't want the brush to get too wet or soaked with Fix+, which makes the application difficult. After that, tap your brush onto the pigment and pat the colors onto the lid.
Below is a comparison between pigment applied without Fix+ on the left, and with Fix+ on the right. Again both applications are done without a base underneath. The flash on the camera takes a bit away from the intensity of the colors but you can still see the difference between the 2.
Paint Pots - For similar reasons to pigments, I like using the 217 for paint pot applications because it covers the lid in one sweep and can sheer out the color to my liking. It is very easy to use with cream products since it is densely packed.
Here I used Fresco Rose paint pot for illustration purposes. Again I don't usually dip the brush into the pot for sanitary purposes. I use a small Q-tip to take out a small amount, place it on top of my hand, and use the 217 to pick up the product. The good thing about cream products like paint pots is that you can sweep the product back and forth without worrying about fall out. I just place the brush onto the middle of the lid or at the outer corner and work my way across the lid using windshield wiping motions. Notice the concentration of the color is at the middle and bottom of the lid, not so much at the top. I like the 217 for this reason because this allows me to concentrate the darker eyeshadows in the crease area.
Overall, the 217 is a very handy brush for other purposes besides eyeshadow application. It is also an awesome tool for blending out harsh lines in the crease. I love to use this to blend out the outer V for a smokey eye look by starting at the outer corner and moving into the upper crease using a circling motion. You can use either windshield wiper or circle motion depending on which you are more comfortable with. I highly recommend picking up this brush if you like pigments, paint pots, or a tool to blend out smokey eyes. I own both the regular and the SE version which is shorter handle. I don't like the SE version as much because it's not hand made and it's scratchy on the eye, so if you are to pick up a 217, I would recommend the regular version because it's much softer on the lids.
Do you own a 217? How do you use it for everyday application?