>>> SpiderCharacteristic.objects.filter(item=SpiderItem.objects.get(article='14773'))
[<SpiderCharacteristic: color - сиреневый>, <SpiderCharacteristic: size - S>]

>>>SpiderItem.objects.filter(Q(spidercharacteristic__characteristic_type=SpiderCharacteristicType.objects.get(name='size'), spidercharacteristic__value='S') & Q(spidercharacteristic__characteristic_type=SpiderCharacteristicType.objects.get(name='color'), spidercharacteristic__value=u'сиреневый'))
...         
[]

spidercharacteristic__characteristic_type=SpiderCharacteristicType.objects.get(name='size')
#
# equal
#
spidercharacteristic__characteristic_type__name="size"

>>> SpiderItem.objects.filter(Q(spidercharacteristic__characteristic_type=SpiderCharacteristicType.objects.get(name='size'),
  spidercharacteristic__value='S') |  Q(spidercharacteristic__characteristic_type=SpiderCharacteristicType.objects.get(name='color'), 
  spidercharacteristic__value=u'сиреневый'))
...         
[<SpiderItem: 14908>, <SpiderItem: 14783 >, <SpiderItem: 14781>, <SpiderItem: 14774>, <SpiderItem: 14773>, <SpiderItem: 14773>, <SpiderItem: 14769>]

>>>SpiderItem.objects.filter(Q(spidercharacteristic__characteristic_type=SpiderCharacteristicType.objects.get(name='size'), spidercharacteristic__value='S') | Q(spidercharacteristic__characteristic_type=SpiderCharacteristicType.objects.get(name='color'), spidercharacteristic__value=u'сиреневый'))
[<SpiderItem: 14908>, <SpiderItem: 14783>, <SpiderItem: 14781>, <SpiderItem: 14774>, <SpiderItem: 14773>, <SpiderItem: 14773>, <SpiderItem: 14769>]

>>> SpiderItem.objects.filter(Q(spidercharacteristic__characteristic_type__name='size', spidercharacteristic__value='S') |  Q(spidercharacteristic__characteristic_type__name='color', spidercharacteristic__value=u'сиреневый'))
[]

SpiderItem.objects.filter( (Q(spidercharacteristic__characteristic_type__name='size') & 
Q(spidercharacteristic__value='S')) |  (Q(spidercharacteristic__characteristic_type__name='color') & Q(spidercharacteristic__value=u'сиреневый')))

>>> SpiderItem.objects.filter( (Q(spidercharacteristic__characteristic_type__name='size') & 
Q(spidercharacteristic__value='S')) |  (Q(spidercharacteristic__characteristic_type__name='color') & Q(spidercharacteristic__value=u'сиреневый')))
[]

>>> SpiderItem.objects.filter(spidercharacteristic__characteristic_type__name='size', spidercharacteristic__value='S')
[<SpiderItem: 14781>, <SpiderItem: 14773>, <SpiderItem: 14769>]

>>> SpiderItem.objects.filter(spidercharacteristic__characteristic_type=SpiderCharacteristicType.objects.get(name='size'), spidercharacteristic__value='S').filter(spidercharacteristic__characteristic_type=SpiderCharacteristicType.objects.get(name='color'), spidercharacteristic__value=u'сиреневый')
[<SpiderItem: 14773>]

.filter(spidercharacteristic__characteristic_type=SpiderCharacteristicType.objects.get(name='color'), spidercharacteristic__value=u'сиреневый')

SpiderItem.objects.filter(Q(spidercharacteristic__value='S') & Q(spidercharacteristic__value=u'сиреневый'))

SpiderItem.objects.filter(spidercharacteristic__value='S').filter(spidercharacteristic__value=u'сиреневый')