Color doesn't match
 

I had my 68 GTO painted a year and a half ago with Electric Blue but the hood and Endura bumper needed repainted. The paint shop just got around to repainting the hood and bumper this week. The color is brighter and when I asked why they said it was the exact color that was used before. I don't see the paint darkening to match over time. Any thoughts ??

Same color, newer batch? Other possibilities include different painter or gun/settings, different temp or humidity. And one that is rarely considered or admitted to, not enough color was applied to achieve 100% hiding of the under coat when the car was painted. More color is now stacked on top and it is now richer.
And no, it isn't going to darken and match later on. Did they claim it would?

The shop didn't do a spray-out prior to applying the paint? That's painting 101.

color match
 

Your painter should have "blended" the new paint into the surrounding old paint areas. Billk

The sealer color under paint can affect color or if they mix colors on site and they missed it by just a touch it will be off.

Sealer color will only affect it if not enough color was applied. Collision shop (cheap out) scenario. See post #2.

Some versions of that color are three stage / tri-coat
Was your original paint job done as tri-coat ?

A lot of the tri-coat colors have two-stage alternates now.
1) They may have cheaped out on you
2) A different painter sprayed it this time
3) 1 & 2

Lesser possibility is if the car stayed with them the whole past 1.5 years and they kept the leftover portions from that time and re-used them.
If they had been thinned - and stored for that long - the tints will change.
It just happens - regardless of theory

All the other suggestions mentioned apply also.

Bottom Line
it's not a completed assignment and the results/excuses are un-professional

I have never heard of a tri coat paint system. Time to do some reading

Color Coat > Pearl Coat > Clear Coat = Tri-Coat or as it is also called 3 Stage

Candy colors can also be 3 Stage if clear is used.

Its like Chief just mentioned .

All your modern Pearlescent Whites are 3 Stage ,
When production cars dating back to the Cadillac Allante in mid/late 80's started making it available to the open market as a factory finish - it caught on fast.
Every manufacturer piled on.
2-3 coats White / 3-4 coats Translucent Pearl / 2-3 coats Clear

Then came the Reds and Blues , mimicking Custom Candy Colors. (fake candy)
Ford Mustang Laser Red
Used a base of a standard type red Metallic
Then coats of a translucent-tinted Red or Red Pearl for deeper/richer color depth
Then Clear

Some of the Blue Versions are same process - ^ as above.

True Candy used a Base of White, Silver or Gold
Then multiple coats of a translucent color (of choice)
Then Clear
True Candy takes highly experienced/highly polished spray-gun operators when doing large objects.

Fake Candy is easier to work with - with less chance of inconsistent/lazy overlaps showing up as terrible dark/light streaks in finished product.
Its why they developed it - for somewhat easier/uniform use in mass production.
Boost sales with the extra Eye-Candy .
It Works too

Then the aftermarkets come up with standard 2-Stage colors that closely resemble the 3-Stage Colors (to an extent) . For some to use on overall repaints.
Less materials required = Less Cost
In some cases it is close enough to use for blendable match repairs , or they just repaint the whole side of the car with it.
Saves time and money vs. Tri-Coat

A lot of todays painters are scared of -or incapable of -total satisfactory results with Tri-Coat.
The "blendable" BaseCoats are useful as a crutch.
Some owners are easier to fool than others.

In some cases on a Tri-Coat , you won't tell for absolute certain whether or not they nailed it until the clear goes on.
- Then it has to pass the "outdoor/sunshine" test too.
Not for the faint of heart , or mediocre.

Never was really a good idea for passenger cars
But sales marketing doesn't worry about the repair aspects.

It (tri-coat) is beautiful stuff if you have an advanced eye for color

Last fall I thought I was going to finish painting what the previous owner started on the car I bought. It was started in Lamborghini orange. This is a pearl tri-coat (white, orange, clear) .
He told me the trick was to paint it white first. I did and nothing matched. I discovered his dad (who he got the car from and actually did the work) never painted it white as a base. It was just grey sealer. I had to respray the whole car white and go from there. I wasn't happy to buy more orange at $400 a quart. It now has a more brilliant color than before.

This picture is of a Plymouth trunk lid that was blended for a friend today. It had damage on the right side that was fixed by my painter. It's a custom tri-coat paint job, blue pearl over black base, with three coats of clear on top. Without direct light to highlight the pearl, it looks black.

Thats a cool combo Steve. :)

"Black Metallics" used to be awful color choices.
Remember when they all used to look like a black car that was just dirty or dusty. lol

Yeah, I never cared for metallic blacks for the same reason. They looked dirty to me as well. Straying off topic more, but to me the hottest color to come along in years is the red that Mazda uses.

Did one of those....made 5 spray out cards...then did eeny meany miney Moe........ That Mazda color looks nice....but just blend it everywhere. Heck ...they don’t even Tri color the jams...check that out...lol . And black metallic sucks...JMHO