help with -duplicate feature

[edavis]

I have command below and I have to repeat the -duplicate argument to achieve an effect where each image last 15 frames before it transitions to another image using morph

convert 1.jpg -duplicate 15 2.jpg -duplicate 15 3.jpg -duplicate 15 -delay 0 -morph 6 c:\\test.ppm

when I do

convert 1.jpg 2.jpg 3.jpg -duplicate 15,0-2 -delay 0 -morph 6 c:\\test.ppm

it doesn't work
is there a way to replace the 3 -duplicate arguments with one ?

[snibgo]

"-duplicate N" copies just the last image, adding N new images. So if you want 15 in total, use "-duplicate 14".

"-morph N" operates on all the images in the current list, adding N interpolated images between each pair.

So if you want 15 static frames, 6 interpolations to the next which is also repeated, and so on, it gets a little messy. For example: generate the morphs first, then generate the duplicates, then use "-insert" or "-swap" to get them in the right order.