I have had several requests regarding Pastel Blue paint. I have been very fortunate to have purchased, some years ago, a '53 that retains its original Pastel Blue paint, which has been lovingly preserved for now almost 70 years. In 1953 Jaguar had just changed from the lacquer paints to synthetic enamels. These, of course were “single" stage paints. For exterior surfaces, there was a good primer applied and then more than one coat of the top coat. All modern car finishes, of course, are done with a “two" stage finish; primer, base coat, clear top coat. Modern paint suppliers generally formulate for two stage paints, but you can get single stage paints if you poke at it hard enough. A picture of the original can of touch-up paint that came with the car is the first photo.
My car has a license plate bracket that has never been on the car and never exposed to the effects of weather. The paint on this bracket is richer and shinier than the paint that is on the car, which, of course has weathered to some extent. The bottom picture shows the license plate bracket on the bonnet of the car. You can see some of the difference, but it is a little more noticeable in person.
I had the local paint shop scan the bracket and mix up some paint to match. Photos of the paint car are attached. Note that the Dupont ChromaBase is designed as a two stage point, with a clear coat to be applied overtop. For anyone restoring a car, I would recommend using a modern paint. They are so much better than the single stage enamels of the day.