Django Image model with Average Color field

image_with_average_color.py

from decimal import Decimal

from django.db import models

class Color(models.Model):
    red = models.DecimalField(blank=False, null=False, decimal_places=2, max_digits=12)
    green = models.DecimalField(blank=False, null=False, decimal_places=2, max_digits=12)
    blue = models.DecimalField(blank=False, null=False, decimal_places=2, max_digits=12)
    alpha = models.DecimalField(blank=False, null=False, decimal_places=2, max_digits=12, default=Decimal(1.0))

    def __str__(self):
        return f'({self.red}, {self.green}, {self.blue})'


class Image(models.Model):
    name = models.CharField(max_length=64, blank=True, null=True)
    average_color = models.OneToOneField(Color, null=True, blank=True, on_delete=models.SET_NULL)
    

    def __str__(self):
        return f'{self.name}: {self.average_color}'

scratch.py

from color.models import *

Image.objects.create(name="Mountain", average_color=Color.objects.create(red=Decimal(0.295), green=Decimal(0.303), blue=Decimal(0.3)))
Image.objects.create(name="Sea", average_color=Color.objects.create(red=Decimal(0.145), green=Decimal(0.30), blue=Decimal(0.6)))
Image.objects.create(name="Sky", average_color=Color.objects.create(red=Decimal(0.3), green=Decimal(0.297), blue=Decimal(0.31)))

target_color = Color(red=Decimal(0.3), green=Decimal(0.3), blue=Decimal(0.3))
search_tolerance = Decimal(0.02)

matched_images = Image.objects.filter(
    average_color__red__gte=target_color.red - search_tolerance, 
    average_color__red__lte=target_color.red + search_tolerance,
    average_color__green__gte=target_color.green - search_tolerance,
    average_color__green__lte=target_color.green + search_tolerance,
    average_color__blue__gte=target_color.blue - search_tolerance,
    average_color__blue__lte=target_color.blue + search_tolerance
)